I would recommend against anything less than a GTX 650 if you were upgrading. The price to performance ratio is just terrible and honestly the 630 isn't a whole lot better than Intel's iGPU tech, however considering the age of that system and it's relatively weak CPU it may be worth it but I can't help but notice this "The Small Form Factor GX620 model, understandably, has room for only half-height expansion cards." That may be an issue when it comes to selecting a GPU.