CPU fan Flipped = great results

[Tiamat]

So, upon overclocking my Radeon 9800pro 256MB (R350 core) to 420/370, my idle temps were 60C with case temp of 40C and that was worrying me. I touched the Zalman heatpipe cooler I am using and it was slightly warm - about as warm as a HDD with a 120mm low rpm fan blowing in it was.

Somehow, CPU heat was getting trapped in the case and accumulating. So, just for kicks I flipped the CPU fan to blow the "wrong way" esp for this heatsink - SLK947U and it now blows out into my side panel, and temps accross the board dropped 10C.

Oddly enough, this heat buildup was not a problem before the overclock of the R350 - and that was the only change.

Now temps are back to decent numbers: 31C case and 45C CPU Idle and 53C load.

Case: SuperLanboy
CPU Fan: Panaflo M1A BX @ 7V.
PSU: Trueblue 480
Mobo: ABIT NF7-S ver2.0

Moral of the story: If you have a small case with 120mm fans, try setting your CPU fan to suck from the heatsink - the heat might exhaust more effectively rather than building up underneath the powersupply, or other areas of the case.

 

[imported_waldo]

Good on ya, and congrats!

 

[Operandi]

Well from my limited experience flipping the fan around doesn?t make much of a difference performance wise when dealing with low speed like your Panaflow M1A @ 7V. It also has the added benefit of promoting better air flow in your system which your seeing now, so that makes sense.

 

[BonzaiDuck]

I'm casually curious as to what provision you had made for case exhaust before flipping your CPU fan.

 

[LifeStealer]

Most companies would suggest flipping fans around in the case when you're building it to see what the best air flow scheme is.

 

[Spike]

Originally posted by: LifeStealer
Most companies would suggest flipping fans around in the case when you're building it to see what the best air flow scheme is.

The reverse flow works best in my setup, though I run an Alpha PAL8045 and they reccomend to have the fan "suck" off the heatsink. I was debating trying the "blow" approach with my new 80 - 92mm adapter and M1A and see what happens, but I am not sure yet.

-spike

 

[Tiamat]

Originally posted by: BonzaiDuck
I'm casually curious as to what provision you had made for case exhaust before flipping your CPU fan.

I have always had a 120mm evercool aluminum at 5V as the exhaust fan.

An added good is my psu fans are spinning 300fpm slower than before. So, Im quite happy with the effects of only reversing the fan flow on the cpu.

If somebody told me that reversing the cpu fan would shave off 10C off the mobo and cpu, I would not have believed them. Im still quite amazed/disbelief that such an incredible temperature difference resulted from what seems to be a small alteration in the system.