I tested the card along with the nVidia GeForce 8800 GTS 640 MB, nVidia GeForce 8800 GTX, and the 512MB version of the HD 2900 XT. Due to the short amount of time we had with this card, I haven't tested CrossFire or SLI configurations but hopefully this will be something I can return to at a later date.
We tested the 3D performance of each card by running our usual set of benchmarks on our standard test bed, the details of which are in the table below. I've now added in Supreme Commander, the awesome real time strategy game, to our test suite. For Company of Heroes and Supreme Commander, we run the inbuilt performance tests, both of which we've found give good representations of the performance of the game. Our other tests are run using our in-house pre-recorded time-demos taken in the most intense sections of each game.
We generally find that any single card configuration struggles to cope at the resolutions demanded by a 30in monitor so we've stuck to testing at 1,920 x 1,200 and 1,600 x 1,200 which represent the most common resolutions that will be used with these cards.
Although Call of Duty 2 continues to be a game the HD 2900 XT struggles with, the extra memory of the 1gig card does make some difference with an average four per cent increase in performance. Fundamentally, though, once anti-aliasing is cranked up, the 8800 GTS is still a better bet.
Conversely, Counter-Strike:Source has tended to favour ATIs cards and we once again see this is this case. Unfortunately, the extra memory has even less affect in this game with an average increase of less than two per cent.
The HD 2900 XT really shines in Prey with it approaching the 8800 GTX in terms of performance. However, in this title the extra memory has next to no affect.
Company of Heroes follows a very similar trend to Counter-Strike: Source with the two HD 2900 XTs sitting comfortably in-between the 8800 GTS and 8800 GTX. However, we once again see a minimal performance increase from the extra memory.
Finally we come to Supreme Commander, the most recent of the games I've tested with. This looks to be a title that favours nVidia's way of doing things as both the 8800 GTX and the 8800 GTS consistently stay ahead of the two HD 2900 XTs. And, to top it off, the extra memory once again makes very little difference.
So, was ATI justified in its original decision? Does the extra cost of doubling the memory on the HD 2900 XT outweigh the gain in performance? I think we can categorically say, yes! While there's no doubt the extra memory will be useful, nay essential, for certain applications, for the average gamer there is little point in paying more.
Now things have had a chance to settle down, drivers have matured, and ATI has done some serious price slashing, the HD 2900 XT (the 512MB version, that is) has proved a worthy competitor to nVidia's 8800 GTS 640MB. The two cards alternate the lead depending on which game is being played but on average both are equally good investments.
It seems ATI made the right decision when it chose not to ship HD 2900 XTs with 1024MB of memory. While doubling the memory quota does improve performance by a small margin, it is nowhere near enough to justify the increase in cost the extra memory would have demanded.