I'm looking at building a mid range gaming computer. The thing that is stumping me is the rails on the power supplies

RAM0 – Kingston ValueRAM 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) Dual Channel Kit Desktop Memory Model KVR1333D3K2/4GR

Motherboard – GIGABYTE GA-870A-UD3 AM3 AMD 870 SATA 6Gb/s USB 3.0 ATX AMD Motherboard

Case + Supply – Antec Nine Hundred + EA650 Black Steel ATX Mid Tower Computer Case 650W Power Supply

Processor – AMD Phenom II X6 1055T Thuban 2.8GHz Socket AM3 125W Six-Core Desktop Processor HDT55TFBGRBOX

Graphics card – EVGA 01G-P3-1158-TR GeForce GTS 250 1GB 256-bit DDR3 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card

Thats what I got so far but like I said I'm confused on the power supply.
If anyones got any different build ideas to play more recent games for 450 pounds I'm happy to here them.

I'm getting Deja vu.

Well it probably is deja vu, it sounds like it.

Reasonable spec, can't fault it. Big big fan of Gigabyte mobos. Damned if I know what your question is though.

Ooops did I not state it clearly enough. My question is, is there more to power supplies than just getting the correct amount of watts? because I'm reading rails and amps and volts….

It's unlikely you'll need to worry about rails, amps and volts with any modern PSU, just worry about the wattage.

Go here, stick in the details of your build and it will tell you waht wattage you need.

um, if it's DDR3 shouldn't you have 3 modules ?

As said above. Its the wattage that counts, though anything over 500 should be OK for most builds.
Personally I am a big fan of corsair powersupplies. Very stable and VERY quiet. Stay away from cheap ones as they will either be noisy or poor quality. Other number to look out for is efficiency rating. The higher the number the better the quality (and the lower your electricity bill!).
Antec are a fairly good brand, so their power supply ought to be halfway decent.

650W? That's a lot of CO2.

Does no-one care about global warming, acidification of the oceans, melting glaciers anymore?

Screw the environment, what's it ever done for us anyway.

if it's DDR3 shouldn't you have 3 modules ?

No, not for AMD processors.

If it's a modern, which it will be, then it'll have all the bits you need. Second Corsair units really are good and yeah cheap ones are crap.

No, not for AMD processors.

Nor for Intel processors that aren't based on the 1366 socket.

That is to say anything except the top end Core i7's, so the new Core i5's and i3's, as well as the lowest core i7's, all take DDR3 RAM but used in pairs.

Alright cheers I help the enviroment enough 🙂

I'd doubt it would ever draw maximum wattage and I'm assuming a 350w psu will draw the same current as a 700w one given the same demand from the processor??

Correct.

That is to say anything except the top end Core i7's

ah, OK, that's what I have…