Power Supply fan: Going from 37cfm to 27cfm ok?

[alkemyst]

It's a Power PC & Cooling 425ATX that comes with a 30dB/37.5CFM fan (actually a nice ball NIDEC), but I want to use a quiet 20dB/27CFM fan.

is 10CFM less (30%) going to be ok?

Thanks

Chris

 

[GAZZA]

Hard to say but I would think that the original fan is rated at those specs for a reason, I guess your trying to reduce the noise by the looks of things but at the cost of cfm.
Have you tried checking around to see if you can find something a little closer that is less noisier ?
You could try getting a thermisor controlled fan to use which would increase speed if and when needed pretty much like the 80x25mm Vantec ThermoFlow Temperature Controlled Fan.

 

[alkemyst]

nothing really comes close to 37.5CFM at that noise level as the NIDEC happens to be the quietest fan at that level. The 20dB/27CFM fans I'd use are also the quietest at that level.

anyone know a minimum CFM that's safe? I just know the short time I had my antec 550W the fans hardly ran.

Chris

 

[BG4533]

A big part of how much airflow you need depends on how much you are stressing the PSU by using a lot of power. If the fan is not thermally controlled, then it is always running at the most airflow it needs to cool it off under full power usage. Plus, PC Power and Cooling make some pretty hefty PSUs that can probably take a lot more stress than the ordinary unit. You should be fine. I think PC power and cooling lists max wattages at certain temps, this might give you an idea to go on. Measure the temp of the exhaust before and after to see the temperature change.

Brian

 

[sodcha0s]

mod the backside of the psu to accept an 80mm fan blowing into the unit. mount it on the outside of the psu of course.... 😉 that should be plenty of airflow.

 

[0roo0roo]

actual cfm depends on how free or pressurized the air is in your case anyhow. i lower mine with a fanbus wired to psu fans.

 

[alkemyst]

I can make the fan blow in or out of the PSU, it already has a 80mm.

I have 3 in fans at 27cfm each, one out fan at 27cfm, and then the PSU fan.

totals: 81 cfm in and either 64.5 cfm out (with louder fan) or 54 cfm out (with quiet fan).

Case is a full tower Addtronics 7896A
Thanks

 

[huesmann]

Note that those cfm specs are without obstructions, i.e. grilles or perforations. You may not actually be getting those flow rates.

 

[Jhhnn]

That's what happens when you're not really awake- you post two blank messages, show everybody how dim you really are...

Anyway, something like a pcp&c supply is fanned for max continuous output in less than optimal circumstances- doesn't seem likely you'll get anwhere near there with your rig. I'd have no qualms about using the fan you propose, or even using one of those slick add-on temp controllers from siliconacoustics (for example) on your existing fan, provided it doesn't already have a temp controller....

 

[Jhhnn]

D'oh!

 

[alkemyst]

Yeah...I understand the cfm max vs cfm in my pc. My intake fans are behind a perforated grill/filter...exhaust blows through a very free flowing grill as the PSU on does (however it has to suck through a bunch of obstructions in the power supply).

My old 300W by PCPower also had a similar fan in it I just found out (35cfm) and I changed to a 26cfm one....

 

[Rotax]

I wouldn't think you'd wanna go to much lower CFM wise on the PSU. Just from my exp the PS seems always have real warm are coming out of it, much more so than any other exhaust fans. Like someone said...but I'd think you'd prob be fine w/ the quieter fan.. but I dunno. Just like everything, heat has its toll on things..so maybe it will shorten its life a bit, but enough to really matter??