Overvolting & wattages?

[Sleeper]

I thought this would be better if I re-posted this in this section for a little more traffic.
I have been messing with my cooling, and was thinking on overvolting my fans by a little bit. I was wondering how the wattage rating is calculated when combining positive and negative electrical potentials.

I run 4 fans controlled by Speedfan, off a "Hi power fan controller"
Intake 120mm Adda .44a 5.2w
Exhaust 80mm Sunon .17a 2.1w
CPU Dual Delta blowers .85a 10.2w ea

My power supply is 450w
+5v -5v +12v -12v +3.3v +5vsb
34a 0.5a 18a 0.8a 25a 2a
170w 2.5w 216w 9.6w 82.5w 10w

If I choose 15.3v as my overvolt, my choices are using:
3.3v (82.5w) with the -12v (9.6w)
or -12v with +3.3v

Is the power rating, the combined rating of the OV rails used?
eg. [email protected] + (-12v)@9.6w = [email protected]
Or, is the max power rating usable, based upon the lowest rating of the individual rails used. eg. 9.6w of the -12v rail.

Does it make any difference having the higher wattage rating on the positive lead of the fan?

Thanks
Paul

 

[Borisw37]

Is the power rating, the combined rating of the OV rails used?
eg. [email protected] + (-12v)@9.6w = [email protected]
Or, is the max power rating usable, based upon the lowest rating of the individual rails used. eg. 9.6w of the -12v rail.

Does it make any difference having the higher wattage rating on the positive lead of the fan?

Thanks
Paul

"Or, is the max power rating usable, based upon the lowest rating of the individual rails used. eg. 9.6w of the -12v rail."
That /\ is correct.
Is this PSU powering the rest of your computer too, or just the fans?
If it is powering the rest of your computer, I would go through and try to figure out power consumption by other components in your system, for each voltage rail. Once you know that, you can determine which rail has the least current draw, and can be used to power the fans. (dont want to overload any particular rail).
Why are you doing this to begin with? Fans are designed to run at 12v. Supplying higher voltage will likely shorten their life. I would advise against doing this, at least not on the CPU fan. If that fan fails, you are srewed. If you want more CFM, just get a more powerful fan...

 

[Sleeper]

Thanks Borisw37
The honest reason I'm looking at this is... I'm bored and I like experiminting (also the weather is still crappy out, so I cant play with my car)
I have been messing with my cooling, by first making a "high powered fan controller" so I could use "Speedfan" to control my fans via predetermined temp settings. (Works like a charm, and the system is very quiet now)
http://www.ocforums.com/showthread.php?t=351815
I then swapped out my Tt Smartfan on my CPU, for a dual Delta blower setup.
A huge difference in cooling, and again much quieter.
http://www.ocforums.com/showthread.php?t=370365
Now, after doing some reading: http://www.ocforums.com/showthread.php?t=375165 I thought I might try overvolting the fans by just a bit. My plan was to only have the "Max" setting there for really heavy loads, but I now see that my PS neg voltage rail won't be able to handle the load, and I dont want to go to the bother of adding a separate power supply.

Paul