GTA IV Requires: (reading from the back of the case)
OS: Windows Vista S1 / Windows XP S3
Memory: 1.5GB on Vista / 1GB on XP + 16GB free HDD space.
Video Card: 256MB nVidia 7900 / 256MB ATI X1900
Processor: Intel Core 2 Duo 1.8GHz / AMD Athlon X2 64 2.4GHz
Conclusion = You should be able to run GTA IV brougtly on low settings. No matter how much you have
memory on your video card, above 512Mb it makes almost no difference at all. So yes, you should be
able to run it, but the question is would you throw your PC out of the window after playing few days?
I'm running everything on medium and some settings on high, and I'm getting 30-50FPS on 1440x900 resolution.
And I have Intel Core 2 Duo E8400, nVidia GeForce 8800GT 512Mb and 3GB of RAM.