the CPU name
>Processor: AMD Phenom(tm) II X4 945 Processor (4 CPUs), ~3.0GHz
But yeah, you also need to consider if your motherboard has a slot for it (Based off your current card I'm assuming it does, but I can't find any 315 on newegg/similar sites to verify) and the power supply, neither of which would be shown on dxdiag