While looking for a new PSU, should I be looking for one with multiple rails, or will 1 be ok? I read a review where having only 1 rail won't protect your system as well as having multiple ones. Is 1 ok if it has over voltage protection?
Antec is an awesome power supply brand, although you may not like their design or functionality choices one model to the next (i personally have the TPQ1200 and i don't care much for the stripe red or the in line capacitor gimmick that takes up space). A good single rail will do with a high amperage to suit a graphics cards and other components requirements, or a multiple rail psu whose amps per rail is enough for your gfx cards requirement (i forget how this works maybe someone else can chime in).
What about it? Multi rail setups can fail much like a bad circuit breaker due to the way the rails distribute power.There are faults to both forms, but a good PSU from iether will be both reliable and dependable.
First - would I select a single rail PSU - Yes, would I select a multi rale PSU - Yes
I have both - I go for quality. Only advantage of a single rail is, You do not have to worry about which rail goes to which - for most quality PSU and most systems today this is not a problem.
To answer your question - When comparing equally "Quality" PSUs is the multirail safer, I'd have to say yes. A short circuit will turn a PSU off in a multirail configuration where as the same malfunction might not in a single rail system.. For a 20 Amp Rail a resitance of less than 0.6 ohms will shut the PSU down( equates to 240 Watts ). For a a single rail rated @ 60 Amps this resistance dropps to 0.2 ohms or 720 Watts. The power is all heat. Saving grace - the 720 Watts may burn the short open quicker than 240 Watts. But id the short is less than that required to trip the PSU, then the Higher wattage is more likely to start a fire.
Above is strickly from an electrical stand point - And I repeat, I would buy either/or as Long is it is Rated as a QUALITY PSU!.
If you have a multirail, say 4 +12 V rails rated @ 20 Amps each With say a 60 Amp max for all for rails.
You would have to insure that you did not try to connect so that a given rail did not exceed 20 Amps. Also say you had 18 Amps being used on the first 3 rails, then you would only have 6 amps for rail 4, NOT 20 Amps.
Example for +12 V Rails:
Rail 1 would go to MB. This would be for your 20/24 pin MB connector, the 4/8 Pin Connector (CPU), and +12 V For GPU (via the PCI-e connector.
Rail 2 would be to the 6/8 Pin GPU Connector.
Rail 3 would possibly be for 2nd GPU 6/8 Pin connector ( This may be from rail 2)
Rail 4 would be to all external Components (to MB), ie SSD/HDDs and DVD drives
It's possible rail 2 could be for the 4/8 pin CPU pwr, then Rail 3 would be for upto two 6/8 pin GPU pwr connectors
The reference to color code refers to the color of the strip on the Positive wire, different color, different rail. And yes, on most of the newer PSUs they have kind of taken the quess work out of the equation. ie, you have no choice in which rail goes to the 20/24 pin MB connector, which rail goes to the 4/8 pin ATA (CPU) MB connector. The 6/8 pin GPU power is set in concrete. That leaves the molex guys hang around for whats left over. O'Weii you get the point -Pick the highest rated quality at the Power you need and don't sweat the small sh(*&*%.