ok, thanks, my GTA IV dont run too good, and i dont understand why:
Intel Xeon quad 2.8 GHz
6 GB RAM
1GB Geforce 9800GT
Your video card is not adequate. its a shame isn't it? I dont know much about Nvidia but the 9800 only has 100 stream processors. That is not good from my understanding. But beats my hd 3450 with only 32 stream processors. You probablyu could do well playing on 800 x 600 monitor resolution with everything on medium high settings. But if you want higher resolution your probably going to have to buy something with more near 300 stream processors. For me I'm looking at getting a HD 3870 or if it goes well a HD 4870. As I dont know much of Nvidia, if you a fan of using of those cards so I can't recommend anything from that.
Actually, I think you'll find that his graphics card is absolutely fine! It probably has more to do with the fact that he's running a processor not designed for gaming, however I don't know much more than that about the Xeon line of processors, so I can't say for sure.