Except for a few cases where Ubuntu 10.04 LTS was the clear winner (namely the Intel Core i7 system again), Windows 7 won more often. This may be due to OpenArena being better optimized to run on the Microsoft operating system with its ioquake3 engine, but this is what you get with the "out of the box" experience provided by this open-source game. Many of the systems were faster by more than twenty frames per second with Windows 7 than Ubuntu 10.04.
While Windows 7 was faster near consistently with this CPU-limited game, the system that produced the most interesting results was the AMD Opteron workstation. With the octal-core Opteron setup that boasted AMD's brand-new FirePro V8800 graphics card that was released last month, its performance was severely hampered under Ubuntu Linux. At 1680 x 1050, for example, the Opteron workstation running Microsoft Windows 7 was 3.37x faster than when it was running Ubuntu 10.04 with the equivalent proprietary driver. The FirePro V8800 may be a brand new card, but it should be well supported on Linux considering that is where many AMD customers use the hardware. When running at 1920 x 1080, the FirePro V8800 setup with Ubuntu was 3.11x faster than when it was run at 1680 x 1050, and even faster than when the game was run at 800 x 600. It seems there may be a few bugs hampering the new FirePro card under Linux with select consumer OpenGL applications.