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Fan on the heatsink makes a significant difference!

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daba

Member
Joined
Jun 16, 2004
Location
Berkeley, CA
Hi folks. I have a V1000B case with 3,0C @ 3,6 using SP94 and ThermalTake smart case fan 92mm. As many of you know, the TT fan can be controlled via a knob. Under full load, the CPU hovers around 36C with the fan turned all the way up (rated 78 cfm according to TT). When I turn it all the way down, it shoots up to ~47C: a clear 10C increase in temperatures. Nonetheless, TT does state at the lowest RPM level, the fan only produces a measly 25 cfm. Back when I had the Vantec Tornado 92mm, producing a whopping 110cfm, the temps only dropped 1-2C. For the noise, I kept my TT and sold the tornado.

The moral of this story? Don't skimp on the fan! Even a great heatsink with a lousy fan can have undesirable cooling performance! In addition, I believe there is a good tradeoff for noise level and performance, which varies from user to user. Simply put, louder does not mean better.
 

mtb856

Member
Joined
Mar 17, 2004
Location
Helping young Meatballs grow...
Another major cause of temp increase is the drop in pressure that the fan is putting out. At higher rpms, there is more pressure coming out of the fan, which pushes the air all the way to base instead of just cooling the HS fins. That is why 38mm thick fans( like the Delta HHE and EHE or the Tornado) are considered to be better coolers, they normally run at higher rpms and produce almost twice the pressure of 25mm fans.

That is also the main reason that you can't use 120mm fans on a HS, most don't produce hardly any air pressure at all, so the air just washes over the fins.... very ineffective for cooling. Notice that there is a difference between air pressure and cfm's... 120mm fans are high cfm, but low pressure ( for the most part, there are a few 120mm fans that are high pressure).

Anyway, hope this helps shed a little light on the subject.


Sweet :D Six Stars!!!
 

Yamiyanazz

Member
Joined
Jan 3, 2004
Location
Oregon
Makes sence...but why did he get better results with the smart fan that with his tornado?

Another thing I noticed is that my 25mm fan cooled almost as well as my 38mm delta (both 92mm). I am not sure exactly how pressure worked here, because I could not control the 25mm thick fan...
 

Electron Chaser

Senior Delta Fanatic
Joined
May 6, 2004
Location
I live by a Delta
Yamiyanazz said:
Makes sence...but why did he get better results with the smart fan that with his tornado?

Another thing I noticed is that my 25mm fan cooled almost as well as my 38mm delta (both 92mm). I am not sure exactly how pressure worked here, because I could not control the 25mm thick fan...

If you read the post again he only got another 1 to 2 C temp drop out of the tornado. The 92 mm Smart Fan II puts out 78.7 CFM at 48.5 dBA which is fantastic for a 25mm fan (Actually some of the best I have seen that is why I use them myself) and will put out 7.2 mm-H2O Max pressure.

The Tornado puts out 119 CFM at 56 dBA and will put out 18mm-H20 Max for pressure.

Which does stand to reason that you will get diminshing returns as you approach the maximum threshold for air cooling.


Me personally I use the tornado sure it is nearly twice as loud as a TT SFII but I want that 1 or 2 C :D
 

OrangeCrush

Registered
Joined
May 30, 2004
Electron Chaser said:
Me personally I use the tornado sure it is nearly twice as loud as a TT SFII but I want that 1 or 2 C :D
Here! Here! Yep, don't mind the Tornado(s) either and believe that a fan is one of the key air cooling components that should not be skimped on -- when every degree counts.
 

CheeZeTM

Member
Joined
Jul 7, 2004
Location
Louisiana
another factor to conside would be the pitch of the fan blades, i dont know how it all works and frankly i dont care right now, but i did a cupple small expirements with a cooling fan yesterday (i was bord so why not cuz up fans with a band saw) i noticed that the 80mm fan i had produced a lot more air after i cut 50% of the chasie off, i dont know what i was trying to do, i think i was going to put a CD on the fan of something, but the fan not "sucks" enoughf to suck up the CD, it is just thrown off due to the rotation though

eaw, i have a smudge on my monitor
 

Yamiyanazz

Member
Joined
Jan 3, 2004
Location
Oregon
Electron Chaser said:
If you read the post again he only got another 1 to 2 C temp drop out of the tornado. The 92 mm Smart Fan II puts out 78.7 CFM at 48.5 dBA which is fantastic for a 25mm fan (Actually some of the best I have seen that is why I use them myself) and will put out 7.2 mm-H2O Max pressure.

The Tornado puts out 119 CFM at 56 dBA and will put out 18mm-H20 Max for pressure.

Which does stand to reason that you will get diminshing returns as you approach the maximum threshold for air cooling.


Me personally I use the tornado sure it is nearly twice as loud as a TT SFII but I want that 1 or 2 C :D


Oh! Got it. I thought he meant that the tornado's high/low only had a 2c difference. Thank you for clearing that one up.
 

austinbmxnig

Member
Joined
Jul 3, 2004
Location
Austin
CheeZeTM said:
another factor to conside would be the pitch of the fan blades, i dont know how it all works and frankly i dont care right now, but i did a cupple small expirements with a cooling fan yesterday (i was bord so why not cuz up fans with a band saw) i noticed that the 80mm fan i had produced a lot more air after i cut 50% of the chasie off, i dont know what i was trying to do, i think i was going to put a CD on the fan of something, but the fan not "sucks" enoughf to suck up the CD, it is just thrown off due to the rotation though

eaw, i have a smudge on my monitor


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