In this demo, the ATI Radeon HD 5870 and Radeon HD 5850 definitely had the performance advantage over their competitors. Using the same graphics options in the DX9 renderer, AMD’s ATI Radeon HD 5870 outperformed the NVIDIA GeForce GTX 285 by 23% at 2560x1600 with 8X MSAA and the highest possible in-game settings. Continuing the trend, the ATI Radeon HD 5850 outperformed the GeForce GTX 275 by about 21% at 2560x1600 in DX9 with 4X MSAA and maximum in-game graphics options.

On the NVIDIA side of the fence, the GeForce GTX 285 outran the GTX 275 by about 19% at 2560x1600 with 8X MSAA. Competition within the AMD’s products was less lop-sided. At 2560x1600 with 8X MSAA the Radeon HD 5870 was a hair under 5% faster than the Radeon HD 5850, and that difference was consistent at a variety of settings.

Now, the image quality enhancements in the DX11 renderer in the DiRT 2 demo did bring with them some degradation in performance. From what we’ve witnessed, the degradation was not so severe as to make the game unplayable using comparable settings, but there is a penalty nonetheless. It is interesting to note that, when running in DX11 with the accompanying performance hit, the Radeon HD 5870 still performed better than the GeForce GTX 285 running in DX9 mode. In fact, it was a touch over 13% faster.

Of course, this is not to say that performance on the NVIDIA based video cards was bad. On the contrary, it was quite good. We are looking at 8X MSAA at 2560x1600 being playable on the GTX 285, and 4X MSAA on the GTX 275. That is certainly an acceptable level of AA given the high resolution at which we tested. The only problem with the GeForce GTX 200 series of video cards in this game is that they do not support DX11. Thus, they do not benefit from the image quality enhancements available in the DX11 renderer