I recently bought a Sapphire 7870 GHz Edition card and i'm trying to figure out how to power it. The only thing that i didn't upgrade is my PSU(dumb, right?). It's an cheesy CODEGEN 500W PSU that is keeping me powered atm. I also have a 95W TDP processor. I'm looking forward to buy a new one pretty quick but for that, i'll need a new case because this old one has a top mounted PSU... Now i have 2 questions:
1. How do i determine which rails will be able to power my graphics card? It uses 2x6 pin PCI-e connectors. My crappy PSU doesn't have these connectors but i have 2x4 pin molex connectors on separate rails. One rail is powering the HDD and the other one is powering the optical drive, nothing else. Will these two be able to carry out the max load wattage since the card doesn't use the 225W available but only 175W under full load.
2. If the first question doesn't work, which PSU should i buy? I could manage to get hands on a SeaSonic SS-520GB(S12II) but i'm really cut on the budget so i'd rather get a Cooler Master B500 PSU since it's half the price. And also a mini question, is it possible to mount a bot mounted PSU on a top mounted case?