When beginning with the ioquake3-powered OpenArena, the native Ubuntu Linux performance beat out Microsoft Windows 7 at the lower resolutions for the highest frame-rate and it was not until 2560 x 1600 that Windows 7 was able to overtake Ubuntu Linux and NVIDIA's proprietary driver. The Wine performance meanwhile with running the Windows binaries atop Ubuntu on the same system -- using both Wine 1.2.1 and Wine 1.3.9 -- was significantly slower. On average, using Wine with OpenArena shaved away around 160 frames per second.
The open-source game was still very much playable as it is not really demanding upon a modern CPU/GPU especially when using the proprietary NVIDIA or ATI/AMD drivers, but still there was a performance hit even with this lightweight game. This is also with using an OpenGL renderer where Wine does not have to translate any Direct3D calls over to OpenGL, so titles in those cases would be faced with an even greater performance hit. The frame-rate under Wine was also stable from 800 x 600 to 1920 x 1080 making it look like that under the conditions the game execution is being bottlenecked by the CPU.
With Urban Terror, the Ubuntu Linux performance again came out ahead of Windows 7. However, when using Wine, there was again a noticeable hit. Running this lightweight OpenGL game under Wine caused the performance to drop back by about 20% compared to the native Linux binary.
With Warsow, which is powered by the Qfusion engine, the results were interesting. At the higher resolutions, the Windows 7 performance pulled ahead of Ubuntu 10.10 with both the native client and the Windows binaries being run by Wine. The Wine performance was very close to the native Ubuntu 10.10 performance with Warsow.