Palit NVIDIA GTX460 in Surround: 1GB vs. 2GB - DiRT 2

Submitted by skipclarke on 26 September, 2010 - 03:16

Article Type: 

Genre: Racing
Surround Support: Excellent

All settings at maximum, including Post Processing at ‘High’. Resolution and AA varied. I quite like DiRT2, so decided to bench based on a player-controlled race: Battersea, three laps, 7 opponents, starting at the back of the grid.

DiRT 2

DiRT2 appears to have a built-in framerate cap at 60fps. I made sure I disabled Vsync both in game and in NVIDIA Control Panel, yet I never saw more than 60fps (even tried 1024x768 to make sure…) as with AvP, it is evident that the 1GB cards cannot cope with Surround at maximum settings. However, I was able to play DiRT 2 with Post Processing on Medium and 0xAA at 6064x1200 on 1GB cards and maintain a minimum of 40fps (data not shown). If I have enough time over the next few weeks, I will go back and slowly step all the settings up from minimum one at a time to show where this VRAM bottleneck occurs. DiRT 2 does appear to suffer from severe performance decreases with bezel correction enabled on 1GB cards. While I would not call 5760x1200 playable, the 7fps minimum occurred in the pre-race camera panning – during racing itself, FPS never dropped to a point where it was noticeably jerky, thus I presume that it was at least 20fps during racing at all times.

DiRT 2

With 2GB cards, framerates pick up exceptionally. In fact, I never intended to test 6064x1200 8xAA, but the framerate at 4xAA was still good, so I decided to try it. This resulted in a very interesting result: average fps was easily playable, but during the pre-race camera pan fps was single digits and after I crossed the finish line framerate actually reported 0fps for a second.

DiRT 2

Looking at the VRAM usage figures, hopefully it becomes evident why 6064x1200 8xAA hit such a performance brick wall: even on a card with 2GB of VRAM, DiRT 2 at this resolution and settings fills it and wants more. Those final few MB of 2048 are needed for each rendered frame – at 6064x1200 each frame displayed takes up 27.76MB in the graphics card VRAM. Again it is interesting to see that the 1GB cards fail to fill the VRAM at extreme settings before choosing to use system RAM instead.