Looks like in the XP verson the gamesetting have been set to Very Low and in the Vista version pumped up to Very High. Look at the Crysis Dx9 vs Dx10 screenshot for a better comparisn. And as far as i am concerned Dx10 will slow down you PC performance by more than 15%. Its simply not worth the sacrifice in performance until you have got something like an 8800GTS. .
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