Voltage tolerances

[Crunchie]

What sort of voltage tolerances are acceptable as in low/high? I've got a fairly new FSP-AX500 (Blue Storm) that is showing a low 12v level. Fluctuates between 11.68v and 11.8v. The 3v and 5v also are a little low but ok imo.
The low 12v has only occurred since moving into the Thermaltake case running 5 case fans on top of the cpu fan and the gpu fan.
Could this be a case of too much of a drain on the 12v rail? Or would the psu be dying? It's only about 6 months old.

[madmat]

The ATX spec is +/- 5% so for 3.3V it's +/- .17V for 5.0V it's +/- .25V and for 12V it's +/- .60V.

Now remember it can be low or high within this range and be in spec.

[Crunchie]

So, theoretically, the 12v can go as low as 12.4 and still be viable? Cool :).

[GHoosdum]

Theoretically, you're still OK if the 12V droops to 11.4. That's a range to be careful in, though. At that point, I'd start being careful about adding any drives or doing any OCing.

[Crunchie]

Here's me thinking that the PSU I bought would be more than enough :(. Would a dual rail PSU be better for running all the fans etc that I have?

[GHoosdum]

Nah, the dual-rail PSUs are better for dual GPU systems. I'd say that you can consider yourself safe, but if you experience any system instability, then you have a possible culprit already lined up, just check your 12V rail. Stability of the rail is more important than actual voltage, to a point. So if you're at 11.4V and it doesn't fluctuate, you probably won't experience any hiccups due to power.

[Crunchie]

Cool. Thanks a lot :).

[GHoosdum]

No problem - good luck!