my old X1900 XT seems to be on its last leg after it had switched off twice due to overheating (I had not cleaned it in a while). The system is quite old, so I don't want to spend too much on a replacement. A slightly better performance would be nice, but the system doesn't allow for any big jump.
The computer is an Opteron 170 on some DFI board, 2 GB RAM, Windows XP. The PSU is either 450W or 500W (have to look it up, but definitely one of the two).
So, what would be my best bet for this system at the moment?
At $80 after a $10 rebate, it is a pretty good deal. It is also a significant increase in performance compared to the X1900XT. So there you go, the best of both worlds; inexpensive and a potential large increase in performance. When you upgrade your PC, you can continue to use the card since a faster CPU will really unlock the full performance of this card.
You can go with the less expensive HD 4670 like the following for $60 after a rebate, but I think spending the extra $20 on the HD 4850 is a better bet especially after you buy a faster CPU.