what is the advantage to having a dual 12 volt rail in comparison to a single?

Next thing you know, you have money missing from your dresser and your daughters knocked up! Ive seen it a hundrend times.

In a nut shell. for example on a dual 12v rail one rail goes to the processor while the other rail goes to the rest of your hardware devices. It's basicly spliting the amps up into two lanes instead of one which allows the amps to run evenly to the cpu and other hardware devices in your system at the same time. You don't want one hardware device like a cpu using using more then it's share of amps on a single 12v rail which would rob the good gpu of it's share of amps, because when that happens it can lead anywhere from pc crashs to hardware burnouts.

it's not so much the watts on a psu that counts it's the amps. I don't care if you have a 600watt psu, if you don't have enough amps on one rail at least 24amps on a single rail or 12 amps each on a dual rail in a nice system like a gaming system for example, then you are just asking for for a hardware burnouts. I have seen people come in here say i have a 500watt psu in my gaming rig, but for some reason my system stopped working, then when someone ask them how much their amps were on that single rail psu they say 14/A. Well there is your problem.

AMD Athlon 64 X2 4600+ OC 2.7ghz
2GB Dual Channel DDR 3200
Nvidia 7900GT
SATA II 2x 300gig 7200rpm 16mb cache RAID-0
Gigabyte Nforce 4 SLI

Little bit of basic electricity 101 missing here. The Wattage of a PS is the product of the voltage times the current, thus a 600 watt PS can theoretically supply 12 volts at 50 amps. A 480 watt PS can supply 12 volts at 40 amps. It is preferable to have twin rail but the processor could never demand more than the PS can supply. Of course there is the 5 volt supplies to cansider but in general they draw small currents, it is usually HDD's that sap the power although I have heard that large memory Video cards can also consume a lot.

That is the biggest fool thing we have ever done. The Atomic bomb will never go off, and I speak as an expert in explosives.
- Admiral William Leahy

Being able to to hold the maxium amps on a 500 watt psu and actually supplying it on the psu itself are 2 diff things altogether.

I don't know if you misunderstood what I wrote, but I was just showing the diff that it all depends upon the quality of the psu itself. An El-cheapo psu is going to give you a lot less amps regardless of the watts on a 12v rail then a quailty psu.

AMD Athlon 64 X2 4600+ OC 2.7ghz
2GB Dual Channel DDR 3200
Nvidia 7900GT
SATA II 2x 300gig 7200rpm 16mb cache RAID-0
Gigabyte Nforce 4 SLI

pckiller,

I supplied you a link to an excellent 'free after rebate' PSU. For your 'old' system, it will be more than sufficent. It doesn't have dual +12v rails because it conforms to the ATX12V 1.2 spec rather than the latest 2.0 spec (dual +12v), but it does have 28A on the single +12v. The Thermaltake PSU that you linked to is OK, but the Ultra 500W unit is better, plus it's FREE with free shipping! You will probably be able to use the Ultra on your next build, the Thermaltake will have to be replaced because it only has 18A on the single +12v, so that's something else to consider. You have to act now though because it HAS to be purchased by 10/31 to qualify for the rebate! It also has one huge cooling fan on the bottom which is preferrable, especially as far as noise is concerned.

Here it is again...figure out a way to pay for it:

http://shop2.outpost.com/product/45...

http://www.ultraproducts.com/produc...

Cobra_R,
In this country, the UK, if anyone supplied a 600 watt, 12 volt PS that couldn't deliver 50 amps he'd be in deep doodoo under the Trade Description Act, cheapo or not!

That is the biggest fool thing we have ever done. The Atomic bomb will never go off, and I speak as an expert in explosives.
- Admiral William Leahy

It's diff in the US. because of are voltage diff.

AMD Athlon 64 X2 4600+ OC 2.7ghz
2GB Dual Channel DDR 3200
Nvidia 7900GT
SATA II 2x 300gig 7200rpm 16mb cache RAID-0
Gigabyte Nforce 4 SLI

"if anyone supplied a 600 watt, 12 volt PS that couldn't deliver 50 amps he'd be in deep doodoo under the Trade Description Act, cheapo or not!"

A 600W PSU with 50A on the +12v rail? Since watts = volts x amps, 12V x 50A = 600A...I'm clear about that part. But what's left to power the +3.3v & +5v rails? I don't believe the ATX12V 2.x standard is specific to the USA, is it?

ATX12V 2.2 Design Guide

Ooops, I meant 600W, not 600A