The Definitive Multi-GPU World Tour - Conclusion #4
Image Quality
It was a bit of a shame that very little of the participating websites actually performed Image Quality tests. Most websites decided to test both solutions at the highest IQ settings with optimizations disabled. It's a very good call but as Rage3D pointed out very well, NVIDIA still compromises on image quality. Obviously with optimizations enabled ATI simply is king of Image Quality and I just do not understand that there's no movement from NVIDIA to do something about it. I still play games sometimes and see the shimmering effect and go WTF?! Companies should not compromise on image quality over a mere 5% performance differential.
What I'd like to see the manufacturers do is very simple: at standard disable all optimizations. And once a user really needs the extra tidbit of performance allow them to enable it. It had to bite NVIDIA in the ass at one point .. consider to be bitten as a lot of consumers are spending heaps amounts of money on their high-end rig demand only the best IQ and therefore simply fly towards ATI.
A perfect example of this is from one of my game Editors. Mike Sowerby was a true NVIDIA devotee. Athlon FX / X2 4800+ processors water-cooled for the CPU and the two GPU's water-cooled as well (2x 6800GT, 2x 6800Ultra, 2x 7800GTX 512MB, then finally onto 2x GeForce 7900 GTX 512MB). Only the best for him, that's Mike. He switched towards two X1900 XT's in Crossfire after his 7900GTX's developed faults. With this article in mind I asked him what made him switch to ATI after being an Nvidia user for so long:
As far as IQ, I'd say the ATI is marginally better, slightly better depth, but that's not to say the nv IQ is bad, I never had a problem with it in the past, fanboys just like to exaggerate these things.
In performance, I'd say its very close. One thing though is with high AA at high res particularly, the ATI card has alot less hit to performance with AA. These are the kind of settings I run everything at (1600x1200 4xAA) and I'm convinced the ATI card has a higher minimum framerate in many games. Particularly noticeable in COD II, 4Xaa 8xAF everything max (on 1x X1900XTX) it chews through it. Min fps of about 40. adv about 50, around 60 max. That isn't too far off what my SLI 7800's did in that game! Single 7900 at those settings had a minimum nearer to 35fps. Disable the AA though and it switches the other way.
In Quake IV though the ATI is noticeably slower... so much so that in multiplayer I had to lower AA from 4x to 2x.
BF2 had no noticeable difference between the pair of them at the same settings tbh.
All in all, the Radeon was over £100 cheaper, so I'm happy with it. Telling the difference between such fast cards is really like splitting hairs.
This is a good example as to why this article is difficult to conclude. While it's clear that NVIDIA owns the overall performance crown, IQ wise the difference is noticeable but only if you take a deeper look. However it's definitely there which makes me state that ATI are the king of image quality (IQ).
Also, when you buy a Crossfire solution you'll be able to run AA & HDR enabled in handful of games. NVIDIA has a very hard time with this. It can do this yet in very unconventional way, totally not well supported by the industry except for two or three games, for example Valve's Half-Life: Lost Coast & Episode One, Far Cry patched and I think the latest Age of Empires. ATI simply has a better working solution here. Again this is stuff you need to weigh into your choice when buying these products.
It's time to wrap up this conclusion as it is getting hideously long and I always tend to ramble on. I'd like to close with a generic recommendation. Whether you choose ATI or NVIDIA it really does not matter in my opinion, it's your call and your money. My recommendation is this: have a good look at the articles on the web. Not necessarily our "definitive" Multi-GPU article as there's nothing definite in this fierce world of videocards at all. Go with what you feel is best, bare in mind what components you need, what budget you have and what kind of resolution versus image quality you want to play your games in. You have PLENTY of good pointers to look at with this nine part article.
Combined we did shown you one of the biggest articles in the history of videocard development, an article where 9 websites engaged into a unique project. Yet we still did not cover even 80% of the possibilities or games out there. There so much more configurations and facts for you to choose from .. some people like the IQ for ATI cards a tad better, ATI has a better AA+HDR solution, NVIDIA offers great selectable performance profiles in their drivers, but what about different resolutions, monitor limitations, GX2 cards dump excessive amounts of heat inside your PC, the X1900 XT cooler makes a lot of noise, power consumption, budget, multi-monitor support, media decoding/acceleration and that list can go on indefinitely.
Honestly as definitive as I would it like it to be it just isn't that clear cut. But one thing is a certain fact, rest assure that the intense competition between both ATI and NVIDIA have taken graphics to a whole new level, one of the results of that battle for better performance is Multi-GPU gaming and that is something both chipzilla's can be proud of as they have achieved and meant so much for the graphics industry and your gaming experience.
Benchmark wise, overall, without a doubt NVIDIA comes out stronger than ATI. NVIDIA simply has a bitching fast and well developed multi-gpu solution at hand. ATI just released that new 6.7 Catalyst driver (was publicly not released at the time I wrote this). This new Catalyst 6.7 driver certainly already makes a difference in a number of the games we have tested since they can now "force" alternate frame rendering.
AFR - Alternate frame rendering. Each graphics core is rendering a frame at a time, odd and even. The full frame is prepared by the CPU and forwarded to the driver, which makes it render on each device to render a frame in turn. This is interleaving. First card A does a frame then card B the other.
What I'm trying to say is that ATI is still playing catch-up and it'll take a while before they are at the same level as NVIDIA is. Many games lack crossfire support. This article shows clearly they need to focus on that kind of driver support in this segment of gaming. Performance is lacking for them and as Mark at Rage3D stated, a lot of games simply are not supported by Crossfire. I'd like to quote Rage 3D here:
NVIDIAs SLI is clearly more stable and mature than ATIs Crossfire, there is no debating that fact. I never experienced any game crashes or rendering errors with SLI, and the one game I was expecting to have some problems with (Pacific Fighters) was apparently recently fixed and now works and scales fine. With Crossfire not only did most games not scale, but I actually had to disable Crossfire just to get them to launch. Elegant degradation is not in ATIs vocabulary, apparently.
When it comes to multi-gpu gaming ATI is already at a level that has improved immensely, ever since the release of the first generation (and rather limited) Crossfire solution. Personally I think it'll take up-to the third generation Crossfire solution before we will see a completely equal performing solution. But no matter what you choose, multi-GPU gaming offers a lot of advantages and offers a frackload of fun. However there are also some disadvantages that need to be mentioned, and those are mainly to be found in compatibility issues here and there on both platforms yet more on ATI's side.
