What quiet 120mm fans do you guys put on your HR-03s??

003 · Post by **003** » Mon Nov 05, 2007 5:14 pm

So I thought that by putting a 120mm fan on my HR-03 which is being used with a heavily over clocked (820/1035) HD2900Pro I would be able to achieve the high volume of air AND very low noise compared to my current 45dB panaflo ultra high speed 68cfm 92mm fan.

Well I tried with my current best (pushes most air) 120mm fan, a Scythe DFS122512L which pushes 60cfm of air at 27dB. The results were horrendous. Idle temperature was 5-6 degrees higher, and when put under a full load the temperature very quickly jumped up to 65+ and I started getting nasty artifacts. With the 92mm panaflo ultra high speed fan, the maximum temperature after a sustained full load was 63c and I never got artifacts.

So what other 120mm fans should I be using instead? I located an online stock of panaflo L1As, and I have one on the way. Will it be be good? If it's not, I am also looking at some of these:
http://www.scythe-usa.com/product/acc/0 ... etail.html
http://www.scythe-usa.com/product/acc/0 ... etail.html
http://www.scythe-usa.com/product/acc/0 ... etail.html

Can anyone offer any help, tips or input?

DerLjubljana · Post by **DerLjubljana** » Mon Nov 05, 2007 7:01 pm

Since there is a dead spot in the middle of the fan, with more air coming through on the outer rim, moving to a 120mm fan probably won't help. If you want to make it quieter, you are going to have to lower the clock on the card.

Also, artifacts at 65 degrees? That seem awfully low...

vick1000 · Post by **vick1000** » Mon Nov 05, 2007 7:02 pm

Sounds like you need to drop your ambient temps first. Or get more air to the fan on the HR. Or change the way it's mounted and/ or direction of airflow.

I have a HR on a 7900GTO and found it works best in the over the top configuration, with the fan pulling air up off the top of the card. Then mount another fan below for cooling the sinks below the card.

003 · Post by **003** » Mon Nov 05, 2007 9:31 pm

Really? So you tested and in that configuration you got the lowest temps? I wouldn't have thought...

What about using one of those new 120mm scythe "slip stream" fans:
http://www.scythe-usa.com/product/acc/0 ... etail.html

They are specifically advertised as having a reduced center hub size and the 68cfm model that is only 24db loud sounds really good.

And if the problem with the 120mm fan is escaping air... what if I affixed one of those 120 to 92mm fan adapters to the fan and put the 92mm end on the heatsink so all the air from the fan would be pushed to the heatsink as if it were a normal 92mm fan.

Would this work?

vick1000 · Post by **vick1000** » Tue Nov 06, 2007 1:45 am

Yes, this configuration gives me the lowest GPU temps, gaining 5c over any other, while only sacraficing about 2c idle/ 3c load on the CPU (Opteron 175@ 3.0ghz, 1.35v, 26c idle/ 43c load).

It seems you have enough CFM with what you have, it's the air getting to the fans or the orientation of the HR and fans that seems to be the problem.

What kind of case is this in, and what kind of air flow though the case? What are your ambient temps?

Sure you could get a quiet fan that moves similiar air volume, but I think you could just slow down the fans you have if you were to fix the real problem.

003 · Post by **003** » Tue Nov 06, 2007 5:29 am

My case is an NZXT lexa, motherboard abit IP35-E with a C2D E6750 @ 3.2GHz with a scythe ninja. The layout is actually extremely similar to yours from the pic, except I don't have as many fans. I have one intake and one exhaust (both 120mm scythe s-flex 800rpm) fan for the case

vick1000 · Post by **vick1000** » Tue Nov 06, 2007 4:30 pm

I think you are going to need to get some more air moving through the case, specifically out the exhaust. All you are doing is throwing heated air at the 2900.

Sadly a 2900 is just too hot a card for a silent computer. Get some 1200rpm fans for intake and exhaust, and maybe another mounted some where inside the case to move intake air toward the 2900.

Lower the room temp if you can, and remove any restrictions from the intakes on the case.

I see you are also OCing the Core Duo, if you have the voltage raised (probably don't need it for 3.2ghz) it will bring up the system temp with the low speed exhaust fan you have now.

thejamppa · Post by **thejamppa** » Tue Nov 06, 2007 9:19 pm

Well, at 31% fan HD 2900 can be heard easily (its I'd think it's over 30 d/BA's by naked ear), but in 25% its very (indeed surprisingly) quiet. All you need to do is to use Atitool or Riva Tuner to set fan speed. But I do agree as owner of HD 2900 Pro, its very, very difficult card for silent computer... But not impossible.