I was wondering why my Mac Pro under XP Pro is delivering lower scores in the 3DMark tests than PCs with similar specs. An Intel Core 2 Quad (2.66GHz) with an ATI Radeon HD 3870 x2 and 2GB RAM scores 19137 3DMarks, while my Mac Pro, 2x2-Core Xeon (2.66GHz,) also with a 3870 x2 and 5GB RAM (Windows doesn't use it all - I know) scores a meager 12136 3DMarks (Both 3DMark06.) I could understand that the Xeons probably aren't as good with games and graphics, but the difference is pretty large. I get equally poor scores compared to the same computer in the PCMark05 tests. (8299 vs. 5136) Any guesses to what might be going on? ALSO: In tests with actual games, my frame rates were lower than comparable systems.