Simple measuring will give you the answer. You will also need to figure if the cards cover any slots you will use. Some will block access. For the power supply, I recommend antec, corsair, enermax, or seasonic for high end cards. 850w is about minimum for two cards. My silverstone 750w full modular has 60 amps on a single 12v rail. The owner upgraded to 1000w in the same brand. I don't know who manufactures silverstone, but mine used was only $55. I use onboard graphics; bought it for full modular feature.