I used to have an MX440, and I will say you will be quite surprised on just how much you can get out of the thing. Up before I swapped it for a GeForce 6800 Vanilla earlier this year, I was able to play CS: Source on it with pretty good results (medium settings, 1024X768, 55FPS average). Granted, mine was an AGP 8X 440, whereas yours is a PCI 420; but I'm guessing you could pull similar results (all a 420 is is an underclocked 440 anyways, so you could probably narrow the gap further if you wanted to).