power supply

A single 12V rail is better, no need to balance the load among multiple rails.
See Arc's reference above.

You can read more on multiple Rails here ......

What is "multiple +12V rails", really?

In most cases, multiple +12V rails are actually just a single +12V source just split up into multiple +12V outputs each with a limited output capability.

There are a few units that actually have two +12V sources, but these are typically very high output power supplies. And in most cases these multiple +12V outputs are split up again to form a total of four, five or six +12V rails for even better safety. To be clear: These REAL multiple +12V rail units are very rare and are all 1000W+ units (Enermax Galaxy, Topower/Tagan "Dual Engine", Thermaltake Tough Power 1000W & 1200W, for example.)

In some cases, the two +12V rail outputs are actually combined to create one large +12V output (Ultra X3 1000W, PC Power & Cooling Turbo Cool 1000W, for example.)

So why do they do they split up +12V rails??

Safety. It's done for the same reason that there's more than one circuit breaker in your house's distribution panel. The goal is to limit the current through each wire to what that wire can carry without getting dangerously hot.

Short circuit protection only works if there's minimal to no resistance in the short (like two wires touching or a hot lead touching a ground like the chassis wall, etc.) If the short occurs on a PCB, in a motor, etc. the resistance in this circuit will typically NOT trip short circuit protection. What does happen is the short essentially creates a load. Without an OCP the load just increases and increases until the wire heats up and the insulation melts off and there's a molten pile of flaming plastic at the bottom of the chassis. This is why rails are split up and "capped off" in most power supplies; there is a safety concern.......

....... Full story

And more over all info here How to Pick the Right Power Supply

i just upgraded to a new psu today a coolermaster Elite Power 500W ATX 12V V2.3 suits my machine ok easy to fit and all the connectors i needed at a fair price. Elite Power 500W - Cooler Master

I just upgreaded to a corsair AX850 psu its overkill but for the price i could not pass it up I got it for 119.00 and corsair dom memory tri ddr3 6gig for 40.00 .. and dont know if its just me but it is running better and faster thin befor it seems, 48 hrs now and i have had no auto shutdowns and restarts and no driver stops and recovers ,, I am going to push it prim it and see if it well do it agen

OCIR said:

I just upgreaded to a corsair AX850 psu its overkill but for the price i could not pass it up I got it for 119.00 and corsair dom memory tri ddr3 6gig for 40.00 .. and dont know if its just me but it is running better and faster thin befor it seems, 48 hrs now and i have had no auto shutdowns and restarts and no driver stops and recovers ,, I am going to push it prim it and see if it well do it agen

i noticed a performance change since i upgraded to a larger psu also i have noticed my cpu fan is working properly good but annoying! its a "screamer" but will use speedfan SpeedFan - Access temperature sensor in your computer software to tweak it up today. i have also noticed the price of ram is very good here in the uk cant say the same about internal hard drives, very expensive compared to a year ago. http://goo.gl/KZ1QE

OCIR said:

is this a good power supply? antec hcp 750 watt high current gamer or should i go for a ocz or corsair i need a 700 to 800 watt psu

I would shoot for a Seasonic made. That model of Antec is made by Delta:

http://whirlpool.net.au/wiki/psu_manufacturers

Corsair TX-750 v2 – Seasonic
Corsair TX-850 v2 – Seasonic

Or just get a Seasonic

well i think all is well i have had my computer on for 6 days and no drivers stoped and no shut downs restarts at all , I think it was the ocz power supply dieing slow

Well, like someone else said, I'm a sucker for Corsair. I built a rig with an HX-650, but kept upgrading and the next rig I got an HX-750 now I reading the power calculators and they say I'm pushing this one. So, I may just go for an HX 1050. I'm tired if buying PSUs. So, if I do that I will have an HX 650 and 750 in the closet. But, i never had a minutes problem with any of them, that's why I stick with and believe in Corsair. But, for those looking;
Johnny Guru recommended PSU's

Who makes it?