All I know is that from what I heard the nVidia FX 5600/5700s or somewhere in the "5000s" area is POS.
I myself have 2 different cards. On my desktop back at home I have a GeForce 4 ti 4600, which runs like a dream (even DirectX 9.0).
On my laptop, I have a Mobility Radeon 9700 pro with 128 MB. It runs perfectly as well.