actually, an 8400 is totally capable for older games. my old laptop had the rough equivalent of a 6600 in it, and i was able to almost max Freelancer on it, at 1440x900. don't just automatically rule it out because it's a few years old, or a budget card. a GTS 240 can destroy an 8800 =) and a 7950GX2 can annihilate it. and an 8400GS with a decent processor (like the i3-530) is way better than an 8800 with a last-gen pentium dual-core or early core 2.
dhsu and bardic, i think you're speaking two different languages. resolution is more closely tied to vram than it is to anything else - meaning that the difference between a card that can drive a 1920x1200 monitor and a 1440x900 monitor is usually 512mb of vram, not necessarily processing power. that said, a GTS 250 would kill anything and make up for a crappy processor on that setup, and they're relatively cheap. a 260 would perform VERY well, as well - as much because of the extra mbs of ram as anything else.
kevin, that card's not that great mainly because PCI is on the same bus that handles everything else (like USB) on your computer. PCI is already limited to a 133mb/s transfer rate, so your tubes are likely just clogged =)
return the card and get a radeon 4650 (55$ or so), buy a new motherboard, probably buy a new processor, maybe some new ram. likely a bigger power supply.
actually, why don't you tell me what computer you've got and i'll tell you what to buy. or you can give me moneys and i'll do it for you.
man, i leave town for two days, and the world explodes. haven't seen this much news in months on this thread.
that said, drumultima is ordering a system from me =) yay! he'll get a quote sometime in the next 12 hours or so, when i'm back home and not on a phone.