MultiGPU Update: Two-GPU Options in Depth
by Derek Wilson on February 23, 2009 7:30 AM EST- Posted in
- GPUs
Who Scales: How Often?
A major topic in the multiGPU arena is software support. And there are two large factors here: how many titles benefit and how much do those titles benefit. In the past we've seen SLI provide scaling more frequently and consistently than CrossFire (especially right when games come out). With CrossFire we'll often see support for older games get broken in newer drivers and then fixed when a review site happens to stumble upon the issue. But we've also noted that when CrossFire worked, it worked really well. It's honestly been a long time since we did a quantitative analysis of how SLI and CrossFire really stack up as technologies, and there's no time like the present.
First we will explore whether performance scaling happened in our suite of games. We've looked at two different metrics to judge our cards, both of which look at percent increase from 2 GPUs. If we consider the success of a multiGPU solution to be contingent on a performance improvement of at least 30% out of a possible 100%, we can count the number of times we see success in our benchmarks as a benchmark. We ran 21 different tests (7 games at 3 different resolutions), so keep that in mind when looking at this of list successes per configuration.
| NVIDIA GeForce GTX 285 | 17 |
| NVIDIA GeForce GTX 280 | 18 |
| NVIDIA GeForce GTX 260 | 20 |
| NVIDIA GeForce 9800 GTX+ | 19 |
| ATI Radeon HD 4870 512MB | 17 |
| ATI Radeon HD 4850 | 19 |
| ATI Radeon HD 4870 1GB | 16 |
Since this takes into account CPU limited cases, our higher performance SLI and CrossFire solutions will see cases where 1680x1050 or even 1920x1200 isn't a high enough resolution to allow for any real improvement. Cards that look good by this metric are ones that both scale well and start off at a low enough performance point so as to allow good scaling to happen even at lower resolutions (well, lower for multiGPU application anyway). This shows the GTX 260 and the 4850 hit a sweet spot in terms of scaling and baseline performance in modern games to provide benefit for a larger number of users (many more people have 1680x1050 and 1920x1200 than 2560x1600 monitors). Because this 9800 GTX+ is older, we see headroom here too.
If we exclude the simply CPU limited cases and look at cases where the multiGPU solution got near zero or negative performance improvement we see a slightly different picture. Our data is on a per game basis, so all of these numbers are out of 7.
| NVIDIA GeForce GTX 285 | 7 |
| NVIDIA GeForce GTX 280 | 7 |
| NVIDIA GeForce GTX 260 | 7 |
| NVIDIA GeForce 9800 GTX+ | 6 |
| ATI Radeon HD 4870 512MB | 6 |
| ATI Radeon HD 4850 | 5 |
| ATI Radeon HD 4870 1GB | 7 |
This shows cases where certain multiGPU configurations have zero value to help improve performance because of some failing of the graphics solution. All these cases happen to be issues at 2560x1600 where the resolution proved too much to handle because of the limited amount of onboard RAM.
It's also important to point out that the Sapphire 4850 X2 doesn't suffer from the problems of the 4850 CrossFire we show here. The Sapphire card scales and performs well in every test we ran.
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nubie - Sunday, March 1, 2009 - link
Have you ever used a tool or edited the game profile yourself?I had an 8800GTS 320MB that I used with AA extensively (Also with 3D stereoscopic), and I was told on a forum to use nHancer to modify the profile into a specific mode of Anti-Aliasing, I am pretty sure it worked. It was the beta 162.50 Quadro drivers I believe, you can just put your card's id into the inf and they install and work great.
It is possible the drivers work great and the control panel/GUI is piss-poor (a theory that may hold water).
I wish that nVidia would open up the drivers a little so that control freaks like myself could really tweak the settings to where I want them.
Razorbladehaze - Monday, February 23, 2009 - link
Yeah In my main rig right now i have a i7 920 with two 1gb 4850's i recently bought a third 4850 and installed it. There was some funky flickering, that i think was driver related in BF2 and HoI2 in 3-way mode, but most games seemed okay. Funny thing is... same thing happened when i tried a 3870x2 & 3870 in 3 way on my older x38 core2. I am really hoping these next articles will come with some additional commentary on image quality.To the person who stated that the 9800gtx+ was comparable to the 4850x2. What R U thinking???
I have never really had a problem with any crossfire setups before except with 3-way and i wonder if it is the odd gpu count and if 4 would eliminate some issues. Looking forward the the upcoming articles, this is mostly a teaser with information many already knew.
I agree that the new format for graphs looks good line graphs are crap visually, but i think the default should be the 1920x1080/1200 that most people are interested in based on your survey data : )
See I pay attention.
SiliconDoc - Wednesday, March 18, 2009 - link
THANK YOU !" Yeah In my main rig right now i have a i7 920 with two 1gb 4850's i recently bought a third 4850 and installed it. There was some funky flickering, that i think was driver related in BF2 and HoI2 in 3-way mode, but most games seemed okay. Funny thing is... same thing happened when i tried a 3870x2 & 3870 in 3 way on my older x38 core2. I am really hoping these next articles will come with some additional commentary on image quality. "
________
Another PERFECT REASON to not mention "image quality" - the red fan boy wins again - assist +7 by Derek !
Amazing.
Thank you.
MagicPants - Monday, February 23, 2009 - link
Have you tried forcing on transparency super-sampling? If you don't edges defined by transparency in the texture won't AA. By default Nvidia (ATI?) only AA edges defined by depth difference.SiliconDoc - Wednesday, March 18, 2009 - link
I've seen one review on that, with the blown up edged images, and the ati cards don't smooth and blurr as well - they have more jaggies - so they HAVE to leave that out here - cause you know Derek loves that red 4850 and all the red cards -Elfear - Monday, February 23, 2009 - link
Derrick (or anyone else for that matter) can you comment on why the 4870 512MB Crossfire solution generally performed better than the 4870X2?SiliconDoc - Wednesday, March 18, 2009 - link
Or WHY the GTX260 isn't praised to the stars for running 20 of 21 tests successfully - taking THE WIN !I guess it doesn;t matter when a gamer spends hundreds and hundreds on their dual gpu setup then it epic fails at games... gosh that wouldn't be irritating, would it ?
Amazing red bias...chizo pointed out the sapphire 4850 / other 4850 driver issues thankfully, while Derek has a special place in his heart for the bluebacked red card, and says so in the article - then translates that to ALL 4850's.
DREAM ON if you think that would happen with ANY GREEN card Derek has ever tested!
MagicPants - Monday, February 23, 2009 - link
I'd like to see an article that rates overall systems in price to performance. Try to get as high as fps for the least amount of money spent.As one reader mentioned frame rate below 15 fps doesn't count because it's unplayable, so just pick a number between 10 and 15 and subtract it from the fps. Maybe vary it by game. Frame rates over 60fps shouldn't count either because most monitors can't even show that.
This would be interesting because even small tweaks would make a difference e.g. adding a $60 sound card might get you 4 or 5 fps in a few games and might pay for itself.
marsbound2024 - Monday, February 23, 2009 - link
It doesn't look like the GTX 260 Core 216 provides much, if any, tangible benefit over the GTX 260 according to these tests. Sure it had some wins, but they weren't very big ones and it also had some loses--albeit not very big ones either. One would be tempted to just get a GTX 260 or 4850 and wait to upgrade until the next generation of cards come out this summer. The time is getting close, anyways.SiliconDoc - Wednesday, March 18, 2009 - link
Good call.Even the 4830 or the 9800GT twice either, or the 9800gtx gts250 or 9600gt or 9600gso twice each - or the ati the ati - uhh... uh... do the reds have their "midrange" filled up ? Uh.. the 4670 ?
LOL
Yeah, nvidia needs more midrange - right ?
LOL
THE RED LIARS ARE SOMETHING ELSE!