I did this way back in like 2008. I was working in IT and snagged an optiplex and had the bright idea to throw a gpu in it and see how it did. Realized a few things, at this particular time the psu did not have the extra connector for the gpu, I should have known that. So I buy one to swap it out, realize Dell had a proprietary mobo connector and was apparently something they did but not all the time. So I had to buy an adapter to make it work. Also had the same issue with getting it to fit as well! It worked great once I took care of all that! Lasted like 4 years.