positive pressure?

[ATi_Loyalist]

i know that airflow is important, and well designed airflow, is more beneficial than 50 fans blowing every which way, but i jsut got a zalman CNPS7000AlCu, and i love it, but since it blows down, why not make the rear panel fans blow in? this would create positive pressure though, is that a big deal? the only places where air is entering is through filtered intakes, so dust isnt a problem, but with positive pressure, im concerned there will be a build up of pressure, potentially causing higher temps? am i wrong i thinking this? there is only the PSU for exhaust, and 4 80mm and 1 92mm intakes.

 

[Carnival Forces]

i don't know the direct answer to your question, however, i can direct to an air-flow-tweak-guide: go to G[H] and read the Unofficial Official Tweak Guide; there's a link to it there (Under General Hardware Tweaks or some such thing).

 

[zer0signal667]

It will not cause higher temps due to pressure, because you're not going to be changing the pressure in your case by any noticeable amount. However, the change in airflow patterns may change your temps, as well as a possible reduction in total case airflow due to mismatched intake/exhaust fan pressures.

 

[lil layzie]

Only way to know for sure is to experiment with it and see if your temps improve.

Trial & error.

 

[Visable-assassin]

im running 7 80mm coolermaster neon LEDs blowing IN and one 120mm panaflo M1a and my PSU blowing out...temps are actually very nice...strange setup I know but on my KD7-RAID abit stuck the god damn case temp sensor near the mosfets so my case temp was always like 130f and with the fans down my case temp hit 180f. everything is running this way since ive been too lazy to change the direction of the fans
all I can say is try it and find out dude.

 

[ScretHate]

Jeez. What kind of case has room for 7 intake fans?

 

[Visable-assassin]

Originally posted by ScretHate
Jeez. What kind of case has room for 7 intake fans?

My PC-75b
2 up front
2 next to the I/O panel
and 2 above the PSU
and 1 on the side

 

[ATi_Loyalist]

well, after further testing it seems that excess poitive pressure is detrimental to temps, i was at 44C idle and 51load, after equalizing the pressure, temps dropped massively to 35idle and 44load, hot damn!

 

[smahoney]

Positive pressure is NOT desireable from a cooling perspective. Air outside of your case is colder than the air inside. Positive pressure would reduce the amount of cooler air getting into your case. Positive pressure also has a side effect that can be even more detrimental for air cooling setups in that it promotes the buildup of dust within a case and especially on your heatsinks making them less efficient at transfering heat since the dust buildup acts as an insulator. Negative pressure will draw more air into your case and promote better airflow and reduce the amount of dust. You should always have one more fan blowing out than blowing in - include power supply fans - preferably drawing in from the bottom and exiting from the top. And try to keep cables and wiring from blocking airflow from hotter components. Occasionally blowing the dust off your heatsinks with an air can is also helpful.

 

[tristam]

ah im so confused, i thought it was the other way around smahoney!

 

[Visable-assassin]

Originally posted by smahoney
Positive pressure is NOT desireable from a cooling perspective. Air outside of your case is colder than the air inside. Positive pressure would reduce the amount of cooler air getting into your case. Positive pressure also has a side effect that can be even more detrimental for air cooling setups in that it promotes the buildup of dust within a case and especially on your heatsinks making them less efficient at transfering heat since the dust buildup acts as an insulator. Negative pressure will draw more air into your case and promote better airflow and reduce the amount of dust. You should always have one more fan blowing out than blowing in - include power supply fans - preferably drawing in from the bottom and exiting from the top. And try to keep cables and wiring from blocking airflow from hotter components. Occasionally blowing the dust off your heatsinks with an air can is also helpful.

How do you figure?
running my case with negative pressure i get shitty temps...I reverse everything and get positive pressure and my temps are very nice. granted im not on air. but even when I was on air i was always slightly putting more in than I was taking out and still got great temps.