MultiGPU Update: Two-GPU Options in Depth
by Derek Wilson on February 23, 2009 7:30 AM EST- Posted in
- GPUs
Final Words
There is quite a bit of data here today, and it can be a little bit daunting to sort through. In every test but one, GeForce GTX 285 SLI leads the way in performance. Often the GTX 280 SLI pops up next. That's surprising considering the fact that AMD doesn't have as heavy hitting a single GPU part. And it also doesn't take into account the fact that these two solutions often come in very low in the "value" lineup and not that much higher in performance than something like the Radeon HD 4870 multiGPU options or even the GeForce GTX 295.
The cheaper Radeon HD 4870 X2 often does better than the GTX 295, and often multiGPU AMD options have better value than the highest end single GPU options from NVIDIA. But the real stand out has to be the Sapphire Radeon HD 4850 X2 2GB. This unique card really shined and held it's own all the way up to 2560x1600. While a 1GB 4850 might not make much sense (the extra RAM only really helps at resolutions where the 4850 can't keep up in terms of processing power), the 1GB of RAM per GPU on the 4850 X2 2GB really helps make this single card multiGPU option high end.
The Sapphire 4850 X2 costs less than a single NVIDIA GTX 280 or 285, and performs better than these as well. While the Radeon HD 4870 X2 is viable as high end single card multiGPU option, it competes at a price point beyond NVIDIA's high end. the 4850 X2 really puts pressure on anything that costs between $300 and $400 from the competition. It's very surprising to us that AMD hasn't pushed this configuration and that Sapphire are the only manufacturer to have put one of these out there.
In general, more than one GPU isn't that necessary for 1920x1200 with the highest quality settings, and the Radeon 4870 1GB or an overclocked GeForce GTX 260 core 216 are good options there. Slower single cards are fine for the high quality at 1680x1050 and multiGPU options are basically wasted at this resolution and lower except in Crysis. As we've seen in past tests, only those with 30" monitors will really benefit from multiple GPUs in their system for now. Of course, there are value-add technologies like PhysX and hopefully sooner rather than later OpenCL will attract more developers to GPU computing. But when were talking multiple graphics cards for rendering it's really not worth it without the highest resolution around.
If you want to break it down, the only NVIDIA single GPU solutions we really recommend as an option are the GeForce GTX 260 variants and/or SLI which are on par with the Radeon 4870 512MB and 1GB depending on the games we chose to test. Really the decision comes down to which games you prefer to play and what features you want. Buying a single GPU solution for more than $300 doesn't make sense with the efficiency of the 4850 X2, and the prices on higher performance multiGPU solutions make them a tough sell really. The GTX 285 SLI is the performance leader, but the cost is just huge.
As we mentioned, this is the first of a series of articles that will explore multiGPU performance. The next article will tackle 3-way SLI and 3-way CrossFireX options. The goal is to extend this look into the 3-way realm, looking at scaling from 1 to 3 and from 2 to 3 cards in a system along side pure performance and value. While this will use much of the same data we've looked at today, the focus will be on 3-way and whether or not it has any real practical use.
While we've already seen 2 GPU performance data, we hope that this more in-depth look than usual helps to illustrate the playing field a bit better. AMD (with the help of Sapphire) really has succeeded at their goal of making single card high end options that compete well with NVIDIA's high end single cards. While the Radeon HD 4870 X2 does compete well with the GeForce GTX 295, the 4850 X2 2GB does a great job of offering higher performance than NVIDIA single GPU options and much more bang for your buck at a price point right below the GTX 280.
Our one caveat with AMD remains driver issues. We are happy with Catalyst 9.2 as it competes with the 8.12 hotfix in terms of stability and performance (and it offers more multiGPU support for recently released games). NVIDIA's GeForce GTX 260 core 216 offers good competition for AMD, and driver support issues don't do AMD any favors. Drivers are even more important when it comes to SLI and CrossFire. SLI enjoys much better support from NVIDIA than CrossFire does from AMD. Because of AMD's driver issues, we often have to wait when new games come out to enjoy proper CrossFire scaling with them. And when hotfixes come out it takes more than a month (usually more like two) to fully integrate changes into a WHQL driver. This is quite disappointing and is really the only strike against the Radeon HD 4850 X2 2GB which is in every other way terrific competition for NVIDIA's lineup.
Sometimes you don't get what you pay for, and with less than linear scaling we do see a reduced value from multiple card solutions. Sometimes getting playability at a higher resolution makes this reduced "value" worth it. Sometimes, CPU and system limits can also reduce value for more than one GPU. And sometimes, like in the case of the Sapphire 4850 X2 2GB, we see a single card that costs the same as two separate lower spec'd (in this case lower memory) parts and can therefore offer great scaling and incredible value.
Stay tuned to see how three cards changes the landscape.
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SiliconDoc - Wednesday, March 18, 2009 - link
Oh, I'm sorry go to that new technolo9gy red series the 3000 series, and get that 3780... that covers that GAP the reds have that they constantly WHINE nvidia has but DOES NOT.Yes, go back a full gpu gen for the reds card midrange...
GOOD GOLLY - how big have the reddies been lying? !?
HUGE!
MagicPants - Monday, February 23, 2009 - link
I know you're trying to isolate and rate only the video cards but the fact of the matter is if you spend $200 on a video card that bottlenecks a $3000 system you have made a poor choice. By your metrics integrated video would "win" a number of tests because it is more or less free.You should add a chart where you include the cost of the system. Also feel free to use something besides i7 965. Spending $1000 on a CPU in an article about CPU thrift seems wrong.
oldscotch - Monday, February 23, 2009 - link
I'm not sure that the article was trying to demonstrate how these cards compare in a $3000.00 system, as much as it was trying to eliminate any possibility of a CPU bottleneck.MagicPants - Monday, February 23, 2009 - link
Sure if the article was about pure performance this would make sense, but in performance per dollar it's out of place.If you build a system for $3000 and stick a $200 gtx 260 in it and get 30 fps you've just paid $106 ($3200/30fps)per fps.
Take that same $3000 dollar system and stick a $500 gtx 295 and assume you get 50 fps in the same game. Now you've paid just $70($3500/50fps) per fps.
In the context of that $3000 system the gtx 295 is the better buy because the system is "bottlenecking" the price.
OSJF - Monday, February 23, 2009 - link
What about micro stuttering in MultiGPU configurations?I just bought a HD4870 1GB today, the only reason i didn't choose a MultiGPU configuration was all the talkings about micro stuttering on german tech websites.
DerekWilson - Monday, February 23, 2009 - link
In general, we don't see micro stuttering except at high resolutions on memory intensive games that show average framerates that are already lowish ... games, hardware and drivers have gotten a bit better on that front when it comes to two GPUs to the point where we don't notice it as a problem when we do our hands on testing with two GPUs.chizow - Monday, February 23, 2009 - link
Nice job on the review Derek, certainly a big step up from recent reviews of the last 4-5 months. A few comments though:1) Would be nice to see what happens and start a step-back, CPU scaling with 1 GPU, 2 GPU and 3 CPU. Obviously you'd have to cut down the number of GPUs tested, but perhaps 1 from each generation as a good starting point for this analysis.
2) Some games where there's clearly artificial frame caps or limits, why wouldn't you remove them in your testing first? For example, Fallout 3 allows you to remove the frame cap/smoothing limit, which would certainly be more useful info than a bunch of SLI configs hitting 60FPS cap.
3) COD5 is interesting though, did you contact Treyarch about the apparent 60FPS limit for single-GPU solutions? I don't recall any such cap with COD4.
4) Is the 4850X2 still dependent on custom drivers from Sapphire? I've read some horror stories about official releases not being compatible with the 4850X2, which would certainly put owners behind the 8-ball as a custom driver would certainly have the highest risk of being dropped when it comes to support.
5) Would've been nice to have seen an overclocked i7 used, since its clearly obvious CPU bottlenecks are going to come into play even more once you go to 3 and 4 GPU solutions, while reducing the gain and scaling for the faster individual solutions.
Lastly, do you plan on discussing or investigating the impact of multi-threaded optimizations from drivers in Vista/Win7? You mentioned it in your DX11 article, but both Nvidia and ATI have already made improvements in their drivers, which seem to be directly credited for some of the recent driver gains. Particularly, I'd like to see if its a WDDM 1.0-1.1 benefit from multi-threaded driver that extends to DX9,10,11 paths, or if its limited strictly to WDDM 1.0-1.1 and DX10+ paths.
Thanks, look forward to the rest.
SiliconDoc - Wednesday, March 18, 2009 - link
Thank you very much." 2) Some games where there's clearly artificial frame caps or limits, why wouldn't you remove them in your testing first? For example, Fallout 3 allows you to remove the frame cap/smoothing limit, which would certainly be more useful info than a bunch of SLI configs hitting 60FPS cap.
3) COD5 is interesting though, did you contact Treyarch about the apparent 60FPS limit for single-GPU solutions? I don't recall any such cap with COD4.
4) Is the 4850X2 still dependent on custom drivers from Sapphire? I've read some horror stories about official releases not being compatible with the 4850X2, which would certainly put owners behind the 8-ball as a custom driver would certainly have the highest risk of being dropped when it comes to support.
"
#2 - a red rooster booster that limits nvidia winning by a large margin- unfairly.
#3 - Ditto
#4 - Ditto de opposite = this one boosts the red card unfairly
Yes, when I said "red fan boy" is all over Derek's articles, I meant it.
DerekWilson - Monday, February 23, 2009 - link
thanks for the feedback ... we'll consider some of this going forward.we did what we could to remove artificial frame caps. in fallout 3 we set ipresentinterval to 0 in both .ini files and framerate does go above 60 -- it just doesn't average above 60 so it looks like a vsync issue when it's an LOD issue.
we didn't contact anyone about COD5, though there's a console variable that's supposed to help but didn't (except for the multiGPU soluitons).
we're looking at doing overclocking tests as a follow up. not 100% on that, but we do see the value.
as for the Sapphire 4850 X2, part of the reason we didn't review it initially was because we couldn't get drivers. Ever since 8.12 we've had full driver support for the X2 from AMD. We didn't use any specialized drivers for that card at all.
we can look at the impact of multithreaded optimizations, but this will likely not come until DX11 as most of the stuff we talked about requires DX11 to work. I'll talk to NVIDIA and AMD about current multithreaded optimizations, and if they say there is anything useful to see in current drivers we'll check it out.
thanks again for the feedback
chizow - Monday, February 23, 2009 - link
Oh and specifically, much better layout/graph display with the resolution selections! :)