Possible system

I'm considering buying an HP desktop with the following specs:

Intel(R) Core(TM) 2 Quad processor Q8200 [2.33GHz]

4GB DDR2-800MHz dual channel SDRAM [4x1024]

1GB ATI Radeon HD 4850

Can anyone tell me how something like this would run modern games like Dead Space, GTA4, Grid, COD4, etc? Thanks

well,depending on your resolutions, probably high-very high.