Postioning of fan on CPU cooler

[StarCapt]

I'll soon start my second build using a CoolerMaster Elite 330 case and a Noctua NH-U9B CPU cooler.

Am I correct that the cooler fan moves air toward the labeled side of the fan?

Also, is it better to pull air from the heatsink or push air through the heatsink or does it matter?

I have read that it is preferable to direct air flow toward the rear of the case where a case fan is exhausting it. Is this correct? Is it critical?

Thanks in advance for helpful replies.

SC

[zburns]

Your rear case exhaust fan will create a negative pressure in the immediate area behind the fan (inside the case). Negative pressure in this area will attract air from all available directions to cancel that pressure. This negative pressure will help, not hinder, the flow of air thu the cooler fin assembly.

I imagine you could use the cooler fan on either side and check your cpu temperature in the BIOS Hardware section to see which location gives you the lowest operating temperature (if you do this, the so called 'test senario' has to be the same).

I have a Sonata III Antec case which is very close to the same dimensions as your case. The position of my cpu on the mobo, and hence the location of my Zalman fan causes the fan right side to be about 3 inches from the rear of my 5 inch drive bays that operate from the case front (same as yours). Let me describe two locations for your fan. As you look in the case if the fan is on the right side of the heat sink then the fan is close to the drive area -- if you use this location how much free area to the right of the fan is there to draw air from?

The other location is for the fan to be on the left of the heatsink as you look into the case; now the fan is somewhat close to the rear exhaust fan; my Zalman about 4 inches from my rear fan. I think you make the call based on open space from the fan. If there is more space on the left between heatsink to the rear exhaust than on the right to the rear of the drive area, and if the drive area is cluttered with drives, the left side might be best (assumes three or four inches between the two fans) If your drive area on the right side is not cluttered with a lot of drives, then the right side probably is best.

The fan should draw air from the right, blow right to left, exhaust in the direction of the case rear fan assembly regardless of the location of the fan (right side or left side). If you do put the fan on the left side of the heatsink assembly, I do suggest you also try it on the right but check the cpu temp for both cases, and choose the location that gives the lowest temp within 1 to 2 degrees.

If the drive bays or wiring does not clutter up the right side and inhibit air flow, the right side is probably ok. As long as there is about 3 to four inches clear between rear exhaust fan and heatsink or heatsink with fan attached on left, left side would be ok. But when you are finished and running, take the time and relocate the fan to the opposite side and recheck temperatures -- assuming there is not a physical interference reason not to do this -- I would not under any circumstances remove the heatsink from the cpu. As long as you can easily move the fan from right to left or vice versa, I would do the double check.

Sorry for the lengthy back and forth, but not knowing the exact location of the cpu and how close the heatsink / fan is to the right side -- sort of creates a "but if . . . situation".

Be glad to answer any more questions.

[StarCapt]

Thanks for your thoughful reply. I appreciate it very much. One last question does the Noctua NH-U9B fan blow air toward the side with the label?

SC

[zburns]

If it is a stick on label that can be peeled off, I do not think a manufacturer 'would write in an instruction document anything to the effect ". . . blow air toward the side with the label . . .". If the label is molded into the plastic, maybe so. Also, there could be some 'few words' molded into the plastic that indicate 'air direction', like an arrow on the narrow top side.

You are bound to have some kind of 'instruction manual or fold up sheet with instructions'. If you do have such, and if the manufacturer meant to discuss the topic of 'air direction', they would mention it in 'writing'. If you find no reference to 'air direction' whatsoever in your cooler documentation, then you have to assume they mean for you to 'run the fan' in order to determine 'air direction'.

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Is there an arrow anywhere on the fan that shows direction of fan blade rotation? The arrow would point along one of the long dimensions, not the thin 'cross' or depth dimension. Post back to me if there is and I can tell you how to determine air direction.