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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MamiyaOtaru - Tuesday, February 24, 2009 - link
So we have to be perfect in every way to point out errors? NBA players shouldn't listen to their coaches because their coaches can't play as well as they do? Game reviewers shouldn't trash a game because they couldn't make a better one?ggathagan - Tuesday, February 24, 2009 - link
When it comes to grammatical errors as insignificant as the ones pointed out, yes.If you're going to be that critical, then you best check your own grammar.
cptnjarhead - Wednesday, February 25, 2009 - link
Grammar shmammar, you guys need to move out of your mom’s basement and get laid. :)bigboxes - Wednesday, February 25, 2009 - link
+1stym - Monday, February 23, 2009 - link
I am curious to see how a pair of radeon 4830 would perform in this lineup. A single one is quite weak at those resolutions, but I am willing to bet a pair of those would hold its own against a single GTX280.Oh, and it would be much cheaper, too ($180 including the bridge).
Could you possibly include that setup next?
DerekWilson - Monday, February 23, 2009 - link
You are right that a single 4830 won't be enough perform on par with these guys ... but I don't think two of them would really be worth it against the GTX 280 except maybe at lower resolutions. The 1GB 4830 will run you at least $145, so you're looking at $290 for two of them and the 4850 X2 2GB is the same price. The 512MB 4830 will be limited by memory usage at higher resolutions just like the 4850 512MB.We might look at the 4830 in CrossFire internally and see if it warrants an update, but so far it isn't in the roadmap for the rest of the series.
stym - Monday, February 23, 2009 - link
I was thinking 512MB 4830s, which are in the $90~$110 price range. That price range is the only reason I mention them, because it puts the price tag of a pair of those in the exact same range as a Radeon 4830 512MB or even a GTX260.You said that a 4850 1GB doesn't make sense, and that's even more obvious for a 4830.
pmonti80 - Monday, February 23, 2009 - link
I find too that this would be an interesting match at the $200+ pricetag.wilkinb - Monday, February 23, 2009 - link
why not just drop AoC, it was bad when it came out, has always had issues and odd results and no one i know played for more then 2 months...If you want to have a mmo, why not use one that people play? and maybe even more mature in development...
I know you will say it adds value, but you dont know its it bad code or showing a different view.
ajoyner - Tuesday, February 24, 2009 - link
Most of the issues with the game are gone. There are currently no other MMO's out there that have the graphics or combat system to tax a gpu like this game. Your comment on testing a game that people play is very subjective. There are many MMO's out there that I would not touch....WOW, cough, cough.....but that doesn't mean other people don't enjoy them. I think having this game as one that is regularly benchmarked adds a great deal of value to the article.