CPU Fan blowing in or out of heatsink?

[rx7i2]

Recently I've just put an aftermarket cooler on my rig and i noticed that the fan airflow was blowing in to the heatsink. Is this safe? It obviously came stock like this but I'm a bit concerned-does it do a better job w/ the airflow out or in?

 

[Sui]

Suck or blow, its all about heatsink design. If it came stock like that you most likly won't see anything good from turning it around.

 

[cwiz]

heat transfer (HT) is drastically improved when the fan is blowing onto the heatsink. HT is directly proportional to the fluid velocity (in your case air) passing over the surface of interest. if the air is being sucked from the sides of the heatsink and out of the fan, the fluid is probably in laminar or transition flow. if the air is being blown down onto the heatsink, it is probably in turbulent flow. Turbulent flow is capable of moving far (more than 2x) heat than laminar and transition flow.

the only negative that i can forsee when blowing down onto the heatsink is the mobo will be in more direct contact with the hot fluid coming off the CPU and possibly raise the temp of the area around the CPU. If your case is respirating reasonably well, however, you will not need to worry about this. (good respiration: make sure you have air INTO and OUT OF your case)

 

[cwiz]

It is thermodynamically impossible for your CPU to be colder than the fluid you are using to cool it with!!!!!!

 

[Sui]

Yes, talking about my quote? I'm quite impressed with myself for actually getting him to say that.

 

[rx7i2]

lol, thanks. Another question - if my intake has less of an airflow than my exhaust will it affect the temp of my case? and what about an exhaust PCI slot fan?

 

[RicoDirenzo]

It is thermodynamically impossible for your CPU to be colder than the fluid you are using to cool it with!!!!!!

Unless the contact surface is cooler than the air......which ain't gonna happen unless you freeze your mobo...........so you are not thinking "outside of the box"...........never use the word "impossible"................................

I do have a pancake for a hat!!!!

 

[kmote]

the fan should blow onto the heatsink so there is no worry there
and also the exhaust should be a little more than the intake, this is to create a slightly lower pressure inside the case than outside
for more info, PM me

 

[rx7i2]

Ah, that makes sense. If i grab one of those vantec 90CFM fans will the air move too fast for an intake fan?