Increased gta4 performance

you would need to upgrade ur grpahics card a lot the 8400 gs is for basically day to day tasks not for gaming

also what speed is ur core 2 processor

2 gb ram should be ok but upgrading to 4 may help a lil

basically first thing u need a better graphics card and that may mean a bigger PSU

second 4gb ram

Seriously though, it doesnt dound like you have a gaming capable rig (aside from the basics ie CS... Quake) so what your looking at is possibly going with a modest upgrade to the power supply, so that it can support the power of a much more dedicated gfx card. Something with at least 512mb ram like a 9800something (like gs or gtx) id recommend getting something like 1gb though if you can afford it because gta loves video memory (at points, it can suck up all 2gb of the 4870x2). That will reep the most benefit. The second and maybe most crucial depending on the issues you may be having is the dual core. GTA also loves having more than 2 cores to play with. alot of ppl complain that their dual core rig, no matter how good the gfx card is, runs the game slow. but quad cores seem to fair better. Then memory is always a good thing to have plus its cheap nowadays so upgrading to 4 or 8gb (with faster speed settings) is a good idea

i have a dc 2.1ghz 8800gt 512 4gb ddr amd the game isnt playable in the city, and thats with vista home premium 64 in dx10 with the os optimized as best i can do so.