Psu Fans

[JackRussell]

(sorry if I've chosen forum section unwisely)

 

My Antec PSU fans before: around 1200 rpm during idle and up to 1400 rpm under load.

 

Recently I've made some circulation improvements (I noticed my intakes weren't pushing as much air as I thought). Fixed the intakes, but now my PSU has reacted by staying around 1200 rpm under load... duh! My psu has that nice 92mm sucking air directly up from my cpu HSF exhaust (my hsf fins point up and down)...

 

I'd like the psu's 92mm and it's exhaust fan to stay at full rpm to keep my case temp and hence load temp as low as possible.

 

Q: anyone ever tried modding the fan wiring in their psu to spin at max all the time? Can anything bad happen? Was thinking I could open her up and rewire the pos and neg wires directly to 12 volt rail and only leave the rpm wires where they were before. As for noise, those fans are never loud anyway. Anyone tried this?

 

Just seems dumb that achieving some success in improving intake leads to downgrade in exhaust. I wonder what the max rpm on those fans would be unregulated.

[crash]

Your PSU is probably not increasing the rpms under load because when you increased the intake volume the exhaust volume was also increased. Get it?

 

The PSU has enough air flowing through it to cool it at low rpms, wheras before it had to work a lot harder to move the same amount of air

 

You can't really hurt anything by hardwiring your fans, it's the same as plugging a fan in only without molex connectors, but remember your warranty will be voided for just a few cfm's more air exhausted, maybe only 3 or 4! Is it worth it?

[JackRussell]

Your PSU is probably not increasing the rpms under load because when you increased the intake volume the exhaust volume was also increased

Before I improved my intake fans, PSU rpm would go up under load. Ambient air was hotter so PSU decided it needed more flow to keep itself cool. I'm seeing this via the psu's rpm feedback wire

 

Now with better intake, I'd like my exhaust output to remain the same as before to get the full benefit of the improvement (extra exhaust out of back-top, not just seeping out anywhere). My PSU disagrees with me, because it's happy with the cooler ambient air for cooling itself. I want the PSU to contribute fully to case exhausting, not just to cooling itself. Those fans may as well contribute as they are nicely situated (92mm right above hsf).

 

You can't really hurt anything by hardwiring your fans, it's the same as plugging a fan in only without molex connectors, but remember your warranty will be voided for just a few cfm's more air exhausted, maybe only 3 or 4! Is it worth it?

 

Yea I figure it probably wouldn't hurt, but thought it worth while just to ask if anyone has done this in case the PSU just does something like automatically shutdown when it detects that it can't control rpm's. Don't mind voiding warranty... I'll open it up eventually anyway to get dust out I figure. But also if those fans go as high as 2000 rpm, then there's alot more cfm's to be had.

 

I don't have air conditioning and not worth it around here for general reasons... in other words it will suddenly be approaching 30C for a week, then down to 20C, maybe even 15C, then back up (hard to decided where to leave OC). But with the temps jumping all summer would at least like to make sure every fan in system is working for good circulation (most air coming in front-bottom, most going out back-top... psu is in good place)

 

Addition:

Sorry this is getting verbose (and off topic too): You could look at it like something that is actually better than a blow-hole case mod... it's effectively like a blow-hole, but right above the HSF. You could even entirely replace the fans in the psu with stronger ones... so you get better exhaust right above HSF and a cooler running PSU to boot (psu exhaust is normally quite warm, so it runs pretty hot normally). But does suck that it can't be done without voiding warranty

Edited May 18, 2004 by JackRussell