Hey guys, pretty much ready to get this build up and running, I just need to select a PSU. I've tried to do some research on it, but frankly I'm still a little confused.
cpu: Phenom II 940 - oc'd 3.4
mobo: asus M3A79-T Deluxe
ram: ocz Platinum 800mhz 4gb
gpu: 2 x HD4870's in xfire.
hdd's: 2 x caviar black 640gb's
hsf: OCZ vendetta II
optical: two very average dvd drives.
Case: Antec 900
So, because of the crossfire, I figured I should have a quite high wattage psu, but I know I need certain amps on a certain rail or some such, and thats where I got confused. an online psu calculator told me this system would draw around 558W or some such, but I think thats in ideal circumstances. Thus I figured about 750W would be about right, and leave me room for the future.
so two questions:
1) is 750w about right, or too high/low
2) these all look quite serviceable, but I need them to fit and reach in an Antec 900 case (thus would being modular help?), so could you guys please wade in with your opinions as to which ones are best?
I thought it was more to do with the amps on a rail, rather than the actual wattages? Do I really need 850w+? that starts getting seriously expensive and I was hoping not to spend too much over £100, like the 3 examples I showed in my first post.
On a side note, the OCZ Platinum RAM needs to have its timings and voltage set manually to achieve the advertised amount.
Overclockers are the only UK stockists of PC P&C that i know of and therefore its a little more expensive. Im a fan of big fat single rails though so that'd be my pick.
The wattage is derived from the rails ampage so its very much about both, however some more shady companies would use a high wattage to make their product look better, with weak rails and efficiency.
one final question though. a 4870 uses two 6pin connectors. this psu comes with 2x 6pin and 2x 6+2pin. so if i want to xfire another 4870 later, could I just use the two 6+2pin connectors as 6pin connectors by not attaching the '+2' bit?
Or do I actually need to find a psu with 4x 6pin connectors?