This may help too http://www.videocardbenchmark.net/high_end_gpus.html

It is also an ATX form factor. I thought it had been said the PSU is OK.

I can't ID the case, but from all appearances, either one of those cards will fit.

Is it a retail case? If so, can you tell me the brand and model? Or is it something like an HP case? If it is retail, the manufacturer should be on the case somewhere. Your Grandpa will probably...

Check The width of your case. If you have a standard size case (ATX) you can put a standard size card in. If you have one of the slim or narrow cases, you would need a low profile card. I hope that...