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‘Impossible’ EmDrive Actually Is Impossible, Comprehensive Test Shows

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Humanity has come a long way in understanding the universe. We’ve got a physical framework that mostly matches our observations, and new technologies have allowed us to analyze the Big Bang and take photos of black holes. But the hypothetical EmDrive rocket engine threatened to upend what we knew about physics… if it worked. After the latest round of testing, we can say with a high degree of certainty that it doesn’t

If you have memories from the 90s, you probably remember the interest in cold fusion, a supposed chemical process that could produce energy from fusion at room temperature instead of millions of degrees (pick your favorite scale, the numbers are all huge). The EmDrive is basically cold fusion for the 21st century. First proposed in 2001, the EmDrive uses an asymmetrical resonator cavity inside which electromagnetic energy can bounce around. There’s no exhaust, but proponents claim the EmDrive generates thrust. 

The idea behind the EmDrive is that the tapered shape of the cavity would reflect radiation in such a way that there was a larger net force exerted on the resonator at one end. Thus, an object could use this “engine” for hyper-efficient propulsion. That would be a direct violation of the conservation of momentum. Interest in the EmDrive was scattered until 2016 when NASA’s Eagelworks lab built a prototype and tested it. According to the team, they detected a small but measurable net force, and that got people interested. 

There was plenty of skepticism about the Eagelworks results, and other teams haven’t been able to duplicate the results. A team from the Dresden University of Technology has completed a comprehensive new test, attempting to replicate the results from Eagelworks. And they found nothing — zero thrust was generated by the Dresden EmDrive as electromagnetic radiation bounced around inside the resonator. 

The Dresden EmDrive is an exact copy of the NASA Eagelworks setup.

The team also sought to explain the Eagelworks results, which they did by varying the experimental design. The Dresden researchers used better measurement techniques to show that the EmDrive doesn’t produce thrust, but by tweaking the measurement scale and changing resonator suspension points, they got the same small apparent thrust as NASA. That confirms the Eagelworks thrust was actually just a thermal effect. The researchers also speculate Eagelworks cherry-picked the data by reporting random fluctuations in a way that didn’t represent the full data set. 

This really does feel like the end of the road for the EmDrive. Unless someone can identify some huge element of physics we have missed, there’s no way this engine can function as described. EmDrive proponents will have to pack it in unless they want to end up like cold fusion cranks from the 90s. That’s just science in action, but it’s also a bit of a bummer because the EmDrive would have changed the world if it wasn’t a fantasy.

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Britain says to ease lockdown next week, will test vaccine passports

Britain’s slow but steady march out of a three-month lockdown remains on track even as coronavirus cases surge elsewhere in Europe, Prime Minister Boris Johnson announced Monday, as he confirmed that businesses from barbers to bookstores will be allowed to reopen next week

Johnson said it’s too soon to decide, however, whether U.K. residents will be able to have summer trips abroad. He confirmed that the government will test out a “vaccine passport” system — a way for people to offer proof they have protection from COVID-19 — as a tool to help travel and large events return safely.

Four weeks after England took its first step out of lockdown by reopening schools, Johnson said Britain’s vaccination program was proceeding well and infections were falling. He said the next step would come as planned on April 12, with the reopening of hairdressers, beauty salons, gyms, non-essential shops and bar and restaurant patios. 

“We set out our road map and we’re sticking to it,” Johnson said during a news conference.

But, he added: “We can’t be complacent. We can see the waves of sickness afflicting other countries, and we’ve seen how this story goes.”

A ban on overnight stays away from home in England will also be lifted April 12, and outdoor venues such as zoos and drive-in cinemas can operate again.

Scotland, Wales and Northern Ireland are following similar but slightly different paths out of lockdown.

Highest death toll in Europe

Britain has recorded almost 127,000 coronavirus deaths, the highest toll in Europe. But infections and deaths both have fallen sharply during the current lockdown and since the start of a vaccination campaign that has given a first dose to more than 31 million people, or six in 10 adults.


People paint red hearts onto the COVID-19 Memorial Wall mourning those who have died, on the Embankment in London on April 5, 2021. (Frank Augstein/The Associated Press)

The government aims to give all adults at least one shot of vaccine by July, and hopes that a combination of vaccination and mass testing will allow indoor socializing and large-scale events to return.

It says all adults and children in England will be encouraged to have routine coronavirus tests twice a week as a way to stamp out new outbreaks. The government said free lateral flow tests will be available free starting Friday by mail, from pharmacies and in workplaces. 

Lateral flow tests give results in minutes but are less accurate than the PCR swab tests used to officially confirm cases of COVID-19. But the government insists they are reliable and will help find people who contract the virus but don’t have symptoms.

Britons are currently banned by law from going on holiday abroad under the extraordinary powers Parliament has given the government to fight the pandemic. The government said Monday it won’t lift the travel ban before May 17 — and maybe later.

“The government hopes people will be able to travel to and from the U.K. to take a summer holiday this year, but it is still too soon to know what is possible,” it said in an official update.

Once travel resumes, Britain will rank countries on a traffic-light system as green, yellow or red based on their level of vaccinations, infections and worrying new virus variants. People arriving from “green” countries will have to be tested but won’t face quarantine.

The government also is testing a system of “COVID-status certification” — often dubbed “vaccine passports” — that would allow people seeking to travel or attend events to show they either have received a coronavirus vaccine, tested negative for the virus, or recently had COVID-19 and therefore have some immunity. 

The return of football

A series of events will start this month, including soccer matches, comedy shows and marathon races. The government said the first events will rely only on testing, “but in later pilots vaccination and acquired immunity are expected to be alternative ways to demonstrate status.”


A vial of of the AstraZeneca COVID-19 vaccine is seen at the Guru Nanak Gurdwara Sikh temple, on the day the first Vaisakhi Vaccine Clinic is launched, in Luton, England, on March 21, 2021. (Alberto Pezzali/The Associated Press)

The issue of vaccine passports has been hotly debated around the world, raising questions about how much governments, employers and venues have a right to know about a person’s virus status. The idea is opposed by a wide swath of British lawmakers, from left-of-center opposition politicians to members of Johnson’s Conservative Party, and the policy could face stiff opposition when it is put before Parliament later this month.

Conservative legislator Graham Brady said vaccine passports would be “intrusive, costly and unnecessary.” The leader of the opposition Labour Party, Keir Starmer, called the idea “un-British.”

The government said vaccine passports were all but unavoidable, since many countries were certain to demand proof of COVID-19 status for entry.

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MLS, NWSL to test concussion substitutes in soccer matches

Major League Soccer, the National Women’s Soccer League and U.S. Soccer, are joining a trial program that will allow teams two additional substitutes for suspected concussions in each match.

The International Football Association Board, which sets the rules for the game, approved the trial for concussion substitutes last December. It is expected to run through August 2022.

U.S. Soccer is working with the top men’s and women’s leagues, as well as the United Soccer League and the National Independent Soccer Association, to implement the pilot program protocol across the sport in the United States.

“We do think it’s incredibly important for players and player safety, and it speaks to our role of being a leader in this area and prioritizing health and safety above really anything else that we do as a league,” said Jeff Agoos, vice-president of competition for MLS.

2 substitutions for suspected concussions

Starting this season, teams can make two substitutions for suspected concussions. That’s in addition to the five substitutions already allowed because of the coronavirus. Normally teams are allowed three total substitutions.

Concussion substitutions can be made even if a player has returned to the field to play. If teams sub out a player because of concussion, the opposing team gets an additional sub — addressing competitive balance concerns.

“It was critical to come together as a sport with our professional leagues and proceed in this pilot program, prioritizing the well-being of our players above all,” Dr. George Chiampas, U.S. Soccer’s chief medical officer, said in a statement. “We’ve worked hard to raise awareness of head injuries in soccer over the last several years, and this change should go a long way in protecting players suspected of suffering a concussion.”

Olympics also eyeing 

The concussion rule was in force during the SheBeleives Cup in February. FIFA is considering whether it will be used at the Tokyo Olympics this summer.

The English Premier League has allowed use of concussion substitutes since early February. West Ham United’s Issa Diop became the first player subbed out because of a suspected concussion in an FA Cup match against Manchester United on Feb. 9.

In MLS, Agoos there will be additional resources to determine is a concussion substitute is needed.

“If a player is injured, obviously the medical staff will be called on to the field for an evaluation,” Agoos told The Associated Press. “If it’s a head injury, the venue medical director may come on and evaluate the player. In parallel, we have an independent group of people [spotters], similar to some of the other sports, that are reviewing the video of that play and then can send that video to the fourth official’s table where the venue medical director, the VMD, is located for further evaluation.”

Additionally, different cards will be used by officials during MLS matches to indicate the kind of substitution being made: White for a normal sub, pink for a concussion sub and blue for an additional sub.

MLS opens its regular season on April 16; the NWSL’s preseason Challenge Cup tournament starts Friday.

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SpaceX Starship SN11 Blows Itself Apart During High-Altitude Test

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The in-development Starship rocket is key to SpaceX’s future plans, from lunar missions to Mars colonization. Elon Musk’s spaceflight company has been open with its Starship testing, even with the results haven’t been flattering. In the most recent test, the Starship SN11 reached an altitude of about eight kilometers, and then something went wrong. We don’t know exactly what happened yet, but the vessel came down in pieces. Musk quipped on Twitter that at least the crater was in the right place. Say what you will about Elon Musk, he’s pretty unflappable, even when his most ambitious aerospace project struggles to get off the ground. 

The Starship is being developed with reusability in mind like the Falcon 9. SpaceX envisions a fleet of reusable Starships that can take off, land, and then fly again after refueling. While it shares this property with the Falcon 9, the two devices don’t share hardware. The Starship is larger, made of different materials, and has new engines. 

SpaceX has thus far only succeeded in landing the rocket after a low altitude test. In the last flight, featuring SN10, the rocket flew high into the atmosphere, and then landed on the launch pad. It looked like everything would work out, but damage to the fuel system from the harder-than-expected landing led to an explosion several minutes later. The new SN11 flight looks like a step backward as it didn’t even reach the ground in one piece. 

The final image from the Starship (see above) live stream featured one of the craft’s three Raptor engines reigniting for the descent sequence. Contact with the vehicle was lost moments later. Musk said following the incident that the issue appeared to be with the number 2 engine, which didn’t reach operating pressure, but it shouldn’t have been needed to get the rocket on the ground safely. Something else, possibly related to the engine, occurred after the landing burn was supposed to start. However, SpaceX can’t begin to piece together the specifics until it can examine the debris later today. 

This failed test is one more potential setback for SpaceX’s aggressive timeline. Musk has said he hopes to fly a group of passengers, including Japanese billionaire Yusaku Maezawa, around the moon and back in 2023. He’s also pushed the idea that Starships could begin transporting Mars colonists in less than a decade, a timeline that most scientists consider unreasonable. Musk might not have a chance to convince everyone his vision is possible if the rocket doesn’t stop exploding.

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Families eager for results as drug companies test vaccines for use on children, teens

On an unusually warm spring morning, a class of seventh and eighth graders exits the doors of Charles Gordon Senior Public School in Scarborough, Ont. They walk single file through the yard, masked and distanced from each other by a strict two metres — a sign of the times in Toronto, where kids only recently returned to in-person schooling after another lockdown.

The day’s lesson is about COVID-19 vaccines, and appropriately, it was being held at an outdoor classroom. Students had been asked to read up on the vaccines and present questions they would like to ask Canadian officials about the inoculations and their distribution.

As vaccines roll out among older adults, many of the questions from this group of students focused on the fact that children aren’t on the current inoculation schedule. Of the vaccines approved in Canada so far, only the Pfizer vaccine has been cleared for people as young as 16 years old, and the other three are currently meant for ages 18 and up.

Their teacher, Tracey Toyama, said the lesson was a natural extension of current events. “They see it every day on social media; they come in, they ask questions,” she said.

“Why are children not more prioritized in terms of receiving the COVID-19 vaccine?” asked one girl.

“Why wouldn’t we vaccinate children so that they don’t put those who are vulnerable at risk?” asked another.

Indeed, since most children tend to experience milder cases of COVID-19, they weren’t prioritized in international vaccine trials. Still, kids do get sick and they can pass on the virus.

In fact, more than 157,000 Canadians aged 19 or younger have caught COVID-19. So until both adults and children are inoculated against the virus, it’s unlikely society will be able to go back to normal.


Students at Charles Gordon Senior Public School in Scarborough, Ont., hold some of their classes outdoors during the pandemic. During this lesson, students discuss the questions they would like to ask Canadian officials about the vaccines and their distribution. (Sarah Bridge/CBC)

In recognition of this, a number of vaccines are now being tested on younger people.

Drug maker Sinovac submitted data to the Chinese government this week saying its vaccine is safe for children between the ages of three and 17.

Pfizer, Moderna, AstraZeneca, and Johnson & Johnson are now testing their COVID-19 vaccines on younger kids, too. Moderna’s trial includes children as young as six months old. Early data from Pfizer on its trials for children aged 12 years and older is expected soon.

Quebec-based Medicago, which is working through Phase 3 adult trials for its plant-based COVID-19 vaccine, says it has plans to move on to younger age groups as data emerges.

According to Nathalie Charland, a senior director with Medicago, the trials will be similar to those they’ve conducted with people aged 18 and up, though children will likely receive half the vaccine dosage.

Along with monitoring each of the test cases to make sure they’re safe, she said, “We will be looking at the immunogenicity of the vaccine candidate to see if what we saw in adults is the same that we see in children.”


Medicago has been conducting clinical trials of its plant-based COVID-19 vaccine on people aged 18 years and older. Nathalie Charland, a senior director with Medicago, says her company has plans to test the vaccine on younger age groups as well. (Medicago)

Dr. Noni MacDonald with Dalhousie University in Halifax said vaccinating children is “incredibly important.”

She said adults were “rightly” prioritized for COVID-19 vaccines because, “children have not been shown to be the big vector of transmitting this virus from one person to another; it’s mostly adults and young people.”

However, MacDonald added, “The problem we have is we know that we need to have the community immunity happen. So, if we have big pockets of children that are not immunized, that community is not immune.”

With variants circulating, she said, the impetus to vaccinate children as soon as possible is strong.

“This is not the end,” she said. “This is a wicked virus and we need to control it in all the ways we can.”

That urgency is especially acute in households where a family member is immunocompromised.

Torontonian Amerie Alvis, 15, has been worried about bringing the virus home to her mom this past year. Her mother, Jaeda Larkin, is a single parent with rheumatoid arthritis.

“What if she does get sick, and I’m all alone?” Alvis said.


Jaeda Larkin, left, and her daughter Amerie Alvis. Amerie has chosen to do online schooling until she is able to get vaccinated, in order to minimize the risk of contracting COVID-19. (Sarah Bridge/CBC)

At nearly 16 years old, Alvis should be eligible for the Pfizer vaccine in a few months and said she is “all for it.”

In the meantime, she has chosen to do online schooling rather than go back to class, in order to minimize the risk to herself and her mom. Alvis said she won’t go back until she gets a shot, but she’s hopeful life could look different next fall.

Having lost some relatives in the U.S. to COVID-19, Larkin is similarly keen to see the two of them vaccinated against the virus.

“The thought of risking my daughter or, you know, potentially having her get sick is terrifying to me,” Larkin said.

Without available vaccine data for kids under 16, some parents of younger children are hesitant to commit just yet.

Torontonians Barry Ayow and Gina Athanasiou aren’t sure whether they’ll want to vaccinate their two youngest kids, who are 12 and 14 years old, against COVID-19 right away.

“I’m willing to experiment on myself. I’m willing to be a guinea pig. But to volunteer my children to be guinea pigs, that’s a different thing, right?” said Ayow.

At the same time, a sense of duty to their older family members and neighbours is weighing on the couple.

“Will duty outweigh our obligation to our kids to make sure that they’re safe? I don’t know,” said Athanasiou, who has concerns about possible side effects of the vaccines on her kids.

She added, “Maybe we’ll feel more comfortable when we have the studies.”


Barry Ayow, right, and Gina Athanasiou say they’re willing to get vaccinated for COIVD-19, but they aren’t sure whether they want to vaccinate their two youngest children right away. (Ousama Farag/CBC)

Dr. MacDonald said parents can be reassured that a push to vaccinate children won’t be coming “out of nowhere.”

“This is going to be based on evidence,” she said.

In fact, according to MacDonald, information about the COVID-19 vaccines will be more robust than what was initially available for previous vaccines, such as polio.

When the time comes for children to get vaccinated, she said, “literally tens of millions of doses of these vaccines will have been used in the population. We’ve never had that kind of volume whenever we’ve used vaccines in children before when we were starting.”

In a show of hands, about half the students in the Grade 7 and 8 class at Charles Gordon Senior Public School said they themselves would take the vaccine based on what they currently know, with others mostly citing the need for more information on their own age group.

What’s clear from nearly all of them during their classroom discussion, though, is that the stress of the pandemic isn’t just affecting adults.

For seventh grader Isaiah Velez, keeping his family and friends safe is a personal priority, he said, as is putting an end to the pandemic. “I miss going out in public and meeting my friends — a lot,” he said.


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AMD Radeon 6700 XT vs. 5700 XT: Putting RDNA2 to the Test

AMD’s 6700 XT launch last week gives us a bit of an unusual opportunity. Typically, generational GPU comparisons are a bit limited because core counts, texture units, and ROP configurations don’t align perfectly between the families. AMD’s Radeon RX 6700 XT is an exception to this rule, and it allows for a tighter comparison of RDNA versus RDNA2 that would otherwise be possible.

The Radeon 6700 XT and 5700 XT both feature 40 CUs, 160 texture mapping units, and 64 render outputs. (2560:160:64). The 5700 XT has a wider memory pipeline with a 256-bit memory bus and 14Gbps GDDR6. This works out to 448GB/s of main memory bandwidth. The 6700 XT, in contrast, has a 192-bit memory bus, 16Gbps GDDR6, 384GB/s of memory bandwidth, and a 96MB L3 cache. Today, we’ll be examining the 5700 XT against the 6700 XT at the same clock speed to measure the performance and efficiency impacts of the new architecture, smaller memory bus, and L3 cache.

GPU-Comparison-Chart-6700XT

According to AMD, switching to a huge L3 cache allowed them to shrink the memory bus while improving performance. There’ve been concerns from readers that this limited memory bus could prove a liability in gaming, given that a 192-bit memory bus on a $ 479 card is highly unusual.

Comparing both GPUs at the same clock allows us to look for any additional IPC (instructions per clock cycle) improvements between the 5700 XT and 6700 XT. RDNA is capable of issuing one instruction per clock cycle, compared with one instruction every four cycles for GCN. This allowed AMD to claim a 1.25x IPC improvement from GCN to RDNA, and while the company hasn’t claimed an equivalent increase from RDNA to RDNA2, we may see signs of low-level optimizations or just the overall impact of the L3 itself.

We’re comparing the performance of the 5700 XT and 6700 XT today, with both cards approximately locked to a 1.85GHz clock speed. We’ll also compare against the 6700 XT at full speed (SAM disabled) to see the card’s native performance and power consumption. A full review of this card, with Nvidia comparison data, will be arriving shortly.

Test Setup, Configuration, and a New Graphing Engine

We’re shifting to a new, more capable graphing engine here at ET. The graph below shows our results in 11 titles for the 5700 XT (1.85GHz). Clicking on any of the color buttons next to a given card will remove that card from the results, allowing you to focus on the others. Click on the button again to restore the data. Data is broken up by tabs, with one resolution per tab.

Game results were combined for the three Total War: Troy benchmark maps (Battle, Campaign, and Siege), leading to the “Combined” score. Similarly, results from Hitman 2’s Miami and Mumbai maps were averaged to produce a single result. Gaps between the cards in these maps were proportional and this averaging does not distort the overall comparison between the three cards in those titles. We’ve still used our classic graphs for a few results that didn’t map neatly into the specific result format used in this article, but the new engine is spiffier (a technical term), so we plan to use it for most projects going forward.

This presentation method prevents us from giving per-game detail settings in the graph body, so we’ll cover those below:

Ashes of the Singularity: Escalation: Crazy Detail, DX12.

Assassin’s Creed: Origins: Ultra Detail, DX11.

Borderlands 3
: Ultra detail, DX12

Deus Ex: Mankind Divided
Very High Detail, 4x MSAA, DX12

Far Cry 5
: Ultra Detail, High Detail Textures enabled, DX11.

Hitman 2 Combined:
Ultra detail, but performance measured by “GPU” frame rate reported via the benchmarking tool. This maintains continuity with the older Hitman results, which were reported the same way. Miami and Mumbai test results combined. Tested in DX12.

Metro Exodus:
: Tested at Extreme Detail, with Hairworks and Advanced Physics disabled. Extreme Detail activates 2xSSAA, effectively rendering the game at 4K, 5K, and 8K when testing 1080p, 1440p, and 4K. Tested in DX12.

Shadow of the Tomb Raider
: Tested at High Detail, with SMAATx2 enabled. Uses DX12.

Strange Brigade
: Ultra Detail, Vulkan.

Total War: Troy Combined
: Ultra detail, DX12.

Total War: Warhammer II
: Ultra detail, Skaven benchmark, DX12.

Of the games we test, Deus Ex: Mankind Divided and Metro Exodus put the heaviest load on the GPUs, by far. DXMD’s multisample antialiasing implementation carries a very heavy penalty and Exodus is effectively rendering in 8K due to the use of supersampled antialiasing.

All games were tested using an AMD Ryzen 9 5900X on an MSI X570 Godlike equipped with 32GB of DDR4-3200 RAM. AMD’s Ryzen 6700 XT launch driver was used to test both the 5700 XT and 6700 XT. ReBAR / SAM was disabled — AMD doesn’t support this feature on the 5700 XT, so we disabled it for our 6700 XT IPC comparison. ReBAR / SAM is also disabled for the 6700 XT “full clock” results, to ensure an apples-to-apples comparison. We’ll have results with SAM enabled in our full 6700 XT review.

The 1.85GHz clock speed is approximate. In-game clocks remain near the minimum value, but this is not absolute. The 6700 XT was allowed to run between 1.85GHz and 1.95GHz and remained near 1.85GHz. The 5700 XT’s clock ranges from 1.75GHz – 1.95GHz, but it mostly remains between 1.8 – 1.9GHz. AMD’s 6700 XT requires a 100MHz GPU clock range and the 5700 XT didn’t respond to our attempts to manually adjust its clock, so we tuned the 6700 XT to the 5700 XT’s default clock range.

These tests will show any high-resolution / high-detail bottleneck that appears on the 6700 XT versus the 5700 XT. If the 6700 XT’s L3 can’t compensate for the increased memory pressure, the 5700 XT should outperform it. The 6700 XT’s default base clock is 2325MHz, or ~1.26x higher than the 1.85GHz minimum value we defined. Low scaling between the 1.85GHz Radeon 6700 XT and the stock-clocked version may mean memory bandwidth pressure is limiting performance.

We’ll also check power efficiency between the cards because AMD claimed a 1.5x increase for RDNA2 over and above RDNA.

Performance Test Results & Analysis

Here’s the good news: There’s no sign that the L3 cache + 192-bit memory bus chokes the 6700 XT in realistic workloads. Only two games show evidence of memory pressure: Metro Exodus and Deus Ex: Mankind Divided. The benchmark settings we use in those two titles make them maximally difficult to render: Deus Ex: Mankind Divided’s MSAA implementation is very expensive, on all GPUs. Metro Exodus’ “Extreme” benchmark preset renders at 2xSSAA. The game may still be output at 4K, but internally the GPU is rendering 8K worth of pixels. Reducing either of these settings to a sane value would immediately resolve the problem.

There is no sign of a memory bottleneck in the 6700 XT versus the 5700 XT in any other game we tested. On the contrary, one game — Far Cry 5 — shows sharply improved results at 4K for the 6700 XT compared with the 5700 XT. We confirmed these gains with repeated testing and confirmed the results. Either the L3 cache or some other aspect of RDNA2 seems to improve FC5 at 4K, in particular.

AMD has said the 6700 XT is intended as a 1440p GPU and our test results suggest that resolution shows the greatest gap between the 5700 XT and 6700 XT when the two are normalized clock-for-clock. Compared against itself, the gap between the 1.85GHz and the stock-clock 6700 XT was also widest at 1440p.

We’ve also included a few quick results in two benchmarks that use different scales than our tests above and were graphed on older templates: Final Fantasy XV and Neon Noir, the latter as a rare ray tracing game that can run on the 5700 XT.

There is no dramatically different data in either set of results. The gap in FFXV is the largest in 1440p but at 1.85GHz the 5700 XT catches (but doesn’t pass) the 6700 XT @ 1.85GHz in 4K. In Neon Noir, the Crytek ray tracing benchmark, the two GPUs hold a steady gap between themselves.

There’s only limited evidence for IPC gains between RDNA and RDNA2. Allowing for a 2-3 percent margin of error on the basis of GPU clock alone, and 2-3 percent for benchmark-to-benchmark variance, most of the gaps between RDNA and RDNA2 disappear. There are three exceptions at 1440p: Ashes of the Singularity (6700 XT is 15 percent faster), Assassin’s Creed: Origins (10 percent faster), and Total War: Warhammer II (8 percent faster).

The aggregate data across all games shows the 6700 XT is 3 percent faster than the 5700 XT at 1080p, 6 percent faster at 1440p, and 5 percent faster in 4K when the two GPUs are compared clock-for-clock. When tested at full speed (with SAM disabled), the full-speed 6700 XT is 1.23x faster than the 5700 XT at 1080p, 1.3x faster at 1440p, and 1.28x faster at 4K.

These clock-for-clock performance results don’t look great for RDNA2 versus RDNA, but we haven’t checked power consumption data. AMD claimed a 1.5x improvement in performance per watt for RDNA2 versus RDNA, and we don’t have much evidence for performance improvements yet. We measured full-load power consumption during the third run of a three-loop Metro Exodus benchmark at 1080p in Extreme Detail.

This is all sorts of interesting. Clock for clock, RDNA2 is much more power-efficient than RDNA. The 5700 XT and 6700 XT perform virtually identically in Exodus at 1080p, and the 6700 XT is drawing nearly 100W less power to do it while fielding 12GB of RAM (up from 8GB) and a 16Gbps RAM clock (1.14x higher than the 14Gbps on the 5700 XT).

The 5700 XT draws 1.37x as much power as the 6700 XT when they’re measured at the same clock and approximate performance level. That’s an impressive achievement for an iterative new architecture without a new process node involved. Unfortunately, it all goes out the window when the clock turns up. At stock clock in Metro Exodus, the 6700 XT with SAM disabled is 1.21x faster than RDNA, but it uses about 3 percent more power. Clearly, AMD has a fairly power-efficient chip at lower clocks, but it’s tapping 100 percent of available clock room to compete more effectively.

RDNA2 unquestionably offers AMD better clock scaling than the company’s GPUs have previously enjoyed, but with a heavy impact on power consumption. AMD pays for a 1.24x performance improvement with a 1.41x increase in power consumption. That’s not far from a 2:1 ratio, and it speaks to the importance of keeping efficiency high and clocks low in GPU architectures. Clock-for-clock, RDNA2 is capable of offering substantial power advantages over RDNA, but AMD has tuned the 6700 XT for performance, not power consumption. A hypothetical 6700 at lower clock could offer substantially better power consumption, but might not compete effectively with down-market Nvidia cards.

When AMD launched RDNA back in 2019, we noted that the company’s efforts to transform its GPUs would take time, and that not nearly enough of it had passed for an equivalent, Ryzen-like transformation of the product family. Looking at RDNA2 versus RDNA, we definitely see the increased power efficiency AMD was chasing in-evidence when the 5700 XT and 6700 XT are compared clock-for-clock. The smaller memory bus and large L3 cache do indeed appear to pay dividends. AMD is still aggressively tuning its GPUs for competitive purposes, but it has found new efficiencies with RDNA compared with GCN and then with RDNA2 compared to RDNA, to enable it to further boost performance.

We’ll examine the competitive and efficiency situation vis-à-vis Nvidia later this week.

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NASA’s Artemis Rocket Aces Its Second Hot Fire Test

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The Space Launch System (SLS) has been in the works for years, but it’s slowly moving toward its first launch. NASA’s new super rocket got a do-over yesterday, executing a perfect hot fire test that lasted more than eight minutes. That’s a substantial improvement over the January test, during which the failsafe system triggered a shutdown after about a minute. With the “Green Run” finally complete, the SLS is almost ready to get into space. 

When complete, the SLS will be the most powerful rocket NASA has ever built. It will leave Earth behind with the aid of two enormous solid rocket boosters and the core stage with its four RS-25 engines. The hot fire test only includes the core stage, which has liquid-fueled engines. The two propellant tanks in the SLS core can hold more than 733,000 gallons of supercooled oxygen and hydrogen fuel. 

When it’s all done, the SLS will be able to hoist very heavy payloads into orbit and send them all over the solar system. It’s the heart of the upcoming Artemis mission, which will return humans to the surface of the moon. The SLS is also the preferred launch platform for NASA’s Europa Clipper, but it’s possible that mission could go to a commercial vehicle if the SLS isn’t ready in time. 

NASA’s doing everything in its power to ensure the SLS doesn’t fall even further behind schedule. Hot fire tests like this involve attaching the rocket to a test stand and running the engines to simulate the tumult of a real launch. The team got valuable data from the January test, but after going over the rocket again, engineers decided the full eight-minute test would help to validate the core stage for launch. Coincidentally, this also shows the SLS can fire long enough for a real launch.

The SLS is a non-reusable vehicle, unlike SpaceX’s still-in-development Starship or the smaller Falcon 9. This SLS still has legs, though. NASA is working on refurbishing the rocket, and then it’ll be shipped off to Kennedy Space Center in Florida. There, engineers will assemble the full rocket with its twin solid boosters and the Orion spacecraft. If all goes as planned, the SLS could have its maiden flight (Artemis 1) in November 2021. This launch won’t have a crew aboard the Orion capsule, but in or around 2024, NASA hopes to land a crew on the moon as part of Artemis 3.

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Toronto FC camp paused after ‘multiple’ team members test positive for COVID-19

Toronto FC’s pre-season has ground to a halt after a number of positive COVID-19 tests.

The MLS team said Monday club personnel are currently isolating and training has halted pending contact tracing and follow-up testing. The club did not identify who tested positive, saying only they were members of the “team delegation.”

The club’s north Toronto training centre has been closed. The club had been practising behind closed doors there and at BMO Field, whose playing surface has underground heating.

GM Ali Curtis said it started with one positive test and is now at “a small handful” of positives, The club is now testing everyone daily while working with local health authorities with the goal of getting “back to training in a safe way.”

Citing privacy concerns, Curtis declined to comment on the condition of those who tested positive.

“We feel good about the strength of the medical protocols. We’re trying to be smart about this and trying to use all our resources to ensure that everyone returns to health and returns to play in a really, really safe way,” he said.

“Every team in every different league has been dealing with this. We were really fortunate in that last year we didn’t have one staff or player test positive during the season. Last season was a great season for us in that respect. This year, we’ve got to respond in the right way to make sure that everyone is as safe as possible.”

Toronto finished out the 2020 campaign in East Hartford, Conn., due to pandemic-related border restrictions. The club plans to begin the season in Florida, with “home” games either in Orlando or Tampa to start.

Toronto opened camp Feb. 17, allowed to begin its pre-season early to prepare for the Canadian Championship final against Forge FC of the Canadian Premier League. While no date has been announced yet for the game, March 20 has been floated.

The winner of the Canadian Championship advances to the Scotiabank CONCACAF Champions League, to meet Mexico’s Club Leon in a round-of-16 tie that opens April 7.

The MLS regular season kicks of April 17.

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NASA’s Perseverance rover makes 1st test drive on Mars

NASA’s newest Mars rover hit the dusty red road this week, putting 6.4 metres on the odometer in its first test drive.

The Perseverance rover ventured from its landing position Thursday, two weeks after landing on the Red Planet to seek signs of past life.

The roundabout, back-and-forth drive lasted just 33 minutes and went so well that the six-wheeled rover was back on the move Friday.

During a news conference Friday, NASA’s Jet Propulsion Laboratory in Pasadena, Calif., shared photos of the tire tracks over and around small rocks.

“I don’t think I’ve ever been happier to see wheel tracks and I’ve seen a lot of them,” said engineer Anais Zarafian. “This is just a huge milestone for the mission.”


As soon as the system checks on Perseverance are complete, the rover will head for an ancient river delta to collect rocks for return to Earth a decade from now.

Scientists are debating whether to take the smoother route to get to the nearby delta or a possibly tougher way with intriguing remnants from that once-watery time three billion to four billion years ago.

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Tournament of Hearts 1st test of Curling Canada’s Calgary bubble

Kerri Einarson will miss having her twin daughters ask her when can they go to the hotel pool.

The skip of the reigning Canadian women’s curling champions says those moments are mental breaks from the intensity of the Scotties Tournament of Hearts.

The 2021 Tournament of Hearts opening Friday starts a run of four spectator-free Curling Canada events in Calgary in a controlled environment to avoid the spread of the COVID-19 virus.

Einarson’s daughters won’t wait by the rink boards at the home end of the ice to celebrate or commiserate as they did on championship weekend in Moose Jaw, Sask., last year.

“They’re my support team,” Einarson said. “Just seeing that excitement in their eyes after mommy gets off the ice from a win is pretty special.

“Not being able to have them there with me, and my family and friends, it’ll be hard.”

The 18 participating teams will likely find curling the most normal aspect of Calgary’s bubble.

What it takes to run a large-scale, indoor sports event in Canada in a pandemic will greet them as soon as they step off the ice.

Curlers were required to quarantine for 3 days

Curling Canada is adopting many of the practices the NHL used to complete its Edmonton and Toronto playoff bubbles last summer, as well as some of Hockey Canada’s protocols for the world men’s under-21 championship Dec. 25 to Jan. 5 in Edmonton.

The Hearts is also a test event for the Canadian men’s curling championship March 5-14, the national mixed doubles championship March 18-26 and the world men’s curling championship April 2-11 all in Calgary’s Markin MacPhail Centre.


“If we get through the Scotties and everything is absolutely successful, we put everyone on the plane on March 1 to go home and everyone was healthy, then it shows our protocols worked,” said Nolan Thiessen, Curling Canada’s director of broadcast, marketing, innovation and event presentation.

Curlers were required to quarantine for three days and be tested before heading to Calgary.


The Markin MacPhail Centre in Calgary will place host to the 2021 Scotties Tournament of Hearts. (Jeff McIntosh/The Canadian press)

Upon arrival, they must produce two negative tests before playing their first game. More tests will be conducted next week.

The athletes are required to wear masks outside hotel rooms until they step on the field of play.

If they want to use the hotel’s pool or gym, only one person at a time is allowed to do so for 45 minutes and must book in advance.

Restaurant meals outside their hotel and socializing with other teams are not allowed.

Curlers ‘want to get here and compete’

Curlers can have meals with teammates and be in teammates’ hotel rooms once they’ve produced their pre-tournament negative tests.

The hotel is just across the Trans-Canada Highway from the arena at Canada Olympic Park. The teams will shuttle themselves back and forth in rental cars.

They’ll undergo a wellness check twice a day with temperatures taken at both the hotel and the arena.

“We just want this to be safe and healthy for everybody,” Thiessen said. “In talking to the curlers, they’ve had so much cancelled this year. They’ve had so much negative news. They want to get here and compete.

“We’re at the point where it’s happening. We’re setting up the building, the athletes are arriving, people are testing, tests are coming back negative, so let’s get going and try this and try to deliver for sports fans in Canada.”

All provinces and territories will be represented, although many associations hand-picked their representatives instead of holding playdowns.

Some top teams thus unable to try for a Hearts berth, two more wild-card teams were added for a total of three this year.

That turns the 2021 Hearts into somewhat of an unofficial Manitoba championship.

All 3 wild-card teams hail from Manitoba

All three wild-card teams hail from that province for a total of five alongside Einarson and six-time champion Jennifer Jones.

The top four teams from each pool of nine advance to the championship round, from which the top three advance to playoffs.

The top seed in the championship round earns a bye to the Feb. 28 final to face the winner of the semifinal.

A Canadian title, prize money of $ 100,000 and a return trip to the 2022 Tournament of Hearts in Thunder Bay, Ont., goes to the winner, but not necessarily a chance at a world championship

The World Curling Federation recently called off March’s women’s championship in Schaffhausen, Switzerland, when local Swiss health authorities wouldn’t approve it.


Jennifer Jones, seen here on Oct. 2, will look for her 7th Scotties title in Calgary. (Geoff Robins/The Canadian Press)

Einarson, Val Sweeting, Shannon Birchard and Briane Meilleur didn’t wear the Maple Leaf last year because the pandemic wiped out the world championship in Prince George, B.C.

A similar fate awaits this year’s winner unless the WCF can find another host city. That wrinkle doesn’t dull Einarson’s motivation to repeat.

“We’re beyond excited to step back on that ice again and treat it like it’s our first bonspiel of the year,” she said. “It’s just a big one.”

Einarson, Jones, Ontario’s Rachel Homan and wild-card entry Tracy Fleury have locked down berths in November’s Olympic trials in Saskatoon.

A Hearts winner other than those four teams will earn a berth in trials.

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