Would it run, yes. Would it run good, no. The sempron would be a bottleneck to the rest of the computer. If you are considering buying a gtx get something like a 7600gt then get a gig of ram and then upgrade your cpu to a 3500+ or something. All that would come to around the price of one gtx.
yea i would have to agree with holyjounk man spend the cash on better system pieces and possible update it in the future when it can run smooth and clean on your system
With an older Socket 754 board the PCI-E will probably support it while not seeing the full performance of the card itself. That model of the newer line of cards was intended more for Socket 939 model boards with the improvement in PCI-Express 16x performance. That would be a little overkill for the board there with no gain for the expense. An older model would run quite well without the high price tag on it.
That can help a little there. The first PCI-E type slots didn't see much over AGP 8x performance. The boards are also single not dual channel as well. Once you are ready for a new build(Socket 939, AM2) then you go after a higher end card for the performance gain then.