GTA IV, 7 vs Vista

This is weird, I have the game on both operating systems, on Vista it will crash periodically, and will freeze, and repeat audio, but on 7 I do not have that problem, but the problem i have on Windows 7 is that it is just slow!

Do you think your pc can handle GTA IV?
What the game REQUIRES to run at atleast like 3 frames per second
* OS: Windows Vista - Service Pack 1 / XP - Service Pack 3
* Processor: Intel Core 2 Duo 1.8Ghz, AMD Athlon X2 64 2.4Ghz
* Memory: 1.5GB, 16GB Free Hard Drive Space
* Video Card: 256MB NVIDIA 7900 / 256MB ATI X1900(or higher)

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