Rear 120MM Fan not doing it's Job

[meansizzler]

Have a Coolermaster Ammo, fitted with stock front 120MM fan keeping Hd's under 32 Degrees, and added a rear 120MM Akasa Amber but seems it is just blowing out cold air, probably cause I have a Silvestone NT06 Cooler, similar to SI-120, which keeps my Overclocked Pentium D 830 Under 42 Degrees Idle, 55 Degrees Load, all the heat is blown around the case, guess it is taken out by the PSU and some probably escapes throguh top Air vent.., so any point in keep the rear fan?..., what do others do with the SI-120?...happy with my temps, just saying is there any point having the rear fan?, doesn't seem to work with the CPU heatsink..

 

[meansizzler]

it will be doing its job, if it is pushing out any air then it is fine. because of the size and power of the fan, say it pushes out 40cfm, and your case has an area of 4 cubic feet, the air in your case is been replaced 10 times every minute in effect (if the front is pulling in the same)

the air will feel cold for 2 reasons, it hasn't spent long enough in the case to get warm and when air blows over your skin it will feel colder. if you're happy with the temps then i'd be tempted just to reduce the speed of the fan, but i would not remove it.

front fan running at 1200RPM
rear fan running at 1400RPM
cpu ran running at 2000RPM and at least 1CM thicker than other fans, cpu fan is HUGE!!!, should I reduce the speed of it?, if I put it down to 1500RPM then it is pretty much inauidiable, loudest thing then would be Zalman VF900