Recently got an Optiplex 745 from the trash, it runs fine, but its missing a hard drive and 3gb of the RAM it was supposed to come with. I replaced the hard drive and got a replacement 8gb of RAM on the way as well as a replacement PSU. I was wondering, as I am not familiar with the technology, what GPU could I put in the machine that wouldnt be bottle necked by the older hardware. I was thinking something like a Nvidia 500 series graphics card. Give me suggestions please. Thank you.