nForce onboard video is said to be on par with a GeForce2MX 200 or so. If you intend to use the onboard video, then nForce420D is the best choice, not nForce220, because the onboard video needs memory bandwidth and the 420D has the dual-channel memory controller. It makes a big difference, judging by the benchmark results:
click for AnandTech review Keep in mind that, for the dual-channel memory controller to do its thing, you need two DIMMs (preferably identical) and must put them in certain slots (consult motherboard manual).
edit: I guess it's worth noting that the nForce 420D is getting over 100fps in Q3A at 640 x 480... definitely "playable"
