Quake III Arena: Windows V. WineX
First of all, I want to say that I was very excited to be running the Windows version of Quake III Arena in Linux. I did not notice any problem with compatibility. However, the frame rates in WineX are truly terrible when compared to either Windows or Linux. Since there is a Linux version of Q3A available, no one should ever use WineX to play Q3A, but it is still interesting to run as a benchmark. Also, keep in mind that even a mere 50 fps is fast enough to play Quake, though there is definitely something weird happening. The frame rates in WineX appear to be independent of the resolution and color depth. The graphics card is definitely not the bottleneck here.
Next, let's look at performance for a popular DirectX 8 game: Max Payne.