Long discussion about frame metering/dual GPU solutions

#1 Posted by Korwin (2828 posts) -

So anyone with a dual GPU solution in their PC is likely aware of the discussion around micro stutter. Recently Nvidia made it's internal testing method for this issue available to the press to usage in evaluating dual card/gpu setups. As a result people were finally able to see some hard evidence for the following.

  • The effectiveness of Nvidia hardware and software based frame metering technology in managing microstutter
  • How AMD's lack if frame metering can really damage the end result of what is a fairly costly investment

Up until now the only evidence for Crossfire's seemingly larger problems with microstutter has been purely anecdotal which understandably meant that many people took it with a grain of salt. However this new FCAT tool really demonstrates that AMD has had a serious problem in the multi-GPU space for some time now. Fortunately as soon as the numbers were laid out in front of them they set to work on some new software level frame metering to try and resolve the issues.

The video bellow (length/tech talk warning) put out by PC Perspective goes through how the new tool works and the results of their original tests. Additionally they discuss the changes that AMD is making with a new prototype driver to address the enormous difference between the two manufacturers.

Personally I'm pretty keen to get my hands on the new AMD driver once it's reached it's final state and pull my old 5870's out of the cupboard for a test run. I retired those things much earlier than intended due to the significant problems I had trying to get a smooth game play experience at high resolutions.

#2 Posted by Andorski (5190 posts) -

So can I get a tl;dr on this issue and be told whether dual SLI setups are worth doing over a single card setup?

#3 Edited by Korwin (2828 posts) -

@andorski said:

So can I get a tl;dr on this issue and be told whether dual SLI setups are worth doing over a single card setup?

Long story short, single card will always be better right up to the point where you hit the biggest and best (dual GPU should always be considered a power user option). At which point Nvidia's SLI is a far more preferable solution to AMD Crossfire as due to technical reasons the perceivable benefit with Crossfire barely exists and in some cases can make things worse. AMD is currently working on the problem after people (myself included) telling them for years that they have a problem as a result of this new data.

Case in point here is the difference between the current way AMD/ATI has been doing things versus their new frame metering prototype driver.

#4 Posted by jgf (382 posts) -

One point I want to make more clear: The problem with AMD Dual-cards is a driver related issue. So it may go away whenever (afaik they are currently working on it) AMD writes a decent driver for these setups. So you do not need to wait for new hardware from AMD.

@korwin said:

@andorski said:

So can I get a tl;dr on this issue and be told whether dual SLI setups are worth doing over a single card setup?

Long story short, single card will always be better right up to the point where you hit the biggest and best (dual GPU should always be considered a power user option). At which point Nvidia's SLI is a far more preferable solution to AMD Crossfire as to to technical reasons the perceivable benefit with Crossfire barely exists and in some cases can make things worse. AMD is currently working on the problem after people (myself included) telling them for years that they have a problem as a result of this new data.

Case in point here is the difference between the current way AMD/ATI has been doing things versus their new frame metering prototype driver.

#5 Posted by thechronodarkness (294 posts) -

Eh, if you use an AMD card, you get studder if you crossfire or not. Its something you just get used to. Lets say you're looking straight forward in a game, getting 70fps. Start to turn the camera or heavy movement, it may drop to 10-15fps for just a split second. Essentially a studder. If you play around 30-35fps normally, you probably don't notice it that much. Its a problem AMD cards have had for since the 5000 generation. But you add a second/third card to the matter, its really going to be noticable. Just split second framedrops essentially. If you're like most of the bombcast crew and use a controller, you probably will get used to it or not even really see it. Keyboard/mouse? If you're like me and use a high sensitivity, its a bit more noticeable.

#6 Edited by kn00tcn (158 posts) -

er, the CF microstutter is consistent & has been there long before the 5 series (i'm a 4870x2 user myself), plus nv SLI has it as well, just less pronounced... single gpu always beats multi

the individual stutters as seen in hitman or fc3 are something else & not THAT common across games

now of course, when capping or using vsync, things change

if single can only do 40fps in a game, while dual can do 70, & your monitor is 60 with vsync on, then you'll certainly have a smoother experience with 2 gpus

#7 Edited by Korwin (2828 posts) -

@kn00tcn said:

er, the CF microstutter is consistent & has been there long before the 5 series (i'm a 4870x2 user myself), plus nv SLI has it as well, just less pronounced... single gpu always beats multi

the individual stutters as seen in hitman or fc3 are something else & not THAT common across games

now of course, when capping or using vsync, things change

if single can only do 40fps in a game, while dual can do 70, & your monitor is 60 with vsync on, then you'll certainly have a smoother experience with 2 gpus

Capping the frame rate with vsync does not resolve the problem, though it can help mitigate but not to a significant extent. Stutter has indeed been a problem long before the 5xxx series from ATI (I never suggested otherwise), however over the years Nvidia have taken steps to clear up the problem significantly while it's only now that AMD has started to take steps to work on the problem (something I'm glad to see them do).

#8 Posted by kn00tcn (158 posts) -

mebe i should have quoted thechronodarkness

if you use an AMD card, you get studder if you crossfire or not.

#9 Edited by Devildoll (877 posts) -

@kn00tcn: technically, no card on the planet has steady rendertimes.

if you run the card under its limits, by framecapping it at 120 when it is able to run 130-160 during any situation in the game, you'd get even frametimes however.

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