Intake or exhaust???

[SupermanCK]

I have a few question about airflow in a case:
1) Is having balanced intake and exhaust air flow the best cooling method?
2) Or rather by having more exhaust air the best? or vice verse?
3) And by having more exhaust air out of the case, would that mean negative pressure??? or the other way around?
maybe i should post this in case and cooling section...but i guess all overclockers have to deal with temp...so that's why i asked it here first...

 

[boi]

It is best to have intake and exhaust equal each other for maximum efficiency. Yes, more exhaust will cause negative pressure in the case.

 

[SupermanCK]

what is the deal with negative pressure that i heard is better for cooling?

 

[THUGSROOK]

wow, id hate to throw this question for a loop but i have had a very odd discovery.
may only pertain to my particular case but anyways, heres my story....

1st heres a pic of my case so you will have a good idea of what im talking about.

you will notice i have 2x 120mm openings in the side panel, 1 120mm blowhole, and i also have a 80mm front and a 80mm rear behind the cpu. of course i have dual fans in my PSU too.

using all these fans in the correct intake / exuast way, i got a pretty decent temp.
but im a smoker so my case was getting extreamly dusty from this, and it was quite loud.
(yes i tried 7v mod)

next i removed the 2 side panel (intake) fans but obviously still had the grills held there and put the side panel back on.
guess what happened?
not much!

cpu temp went up 1*C as far as i could tell but that could just be typical flux.
my board did go up 1*C but only at idle but not at max.
my vid card overclock did not need to change at all.
....and its much quieter, and less dusty

maybe the holes w/ grilles (in the right locations) using mostly exaust fans (to pull air in from those locations) has merit?

than again maybe not

BTW: this was on a p4 1.5 willy @ 2.0ghz! (you thought AMDs were hot? you aint felt nothing!)

 

[Insidious]

Certainly, you can get to a point of diminishing returns when it comes to moving air in the case.

With a decent HSF and moderate airflow, you have pretty much what you are going to get with air cooling.

In theory, heat transfer will always increase with increased cooling medium flow rates (air for your rig). However,

don't forget that fans actually heat the air they move (just like a fast blender can make hot soup)

Also, your PSU has to condition the power used to run those fans and that means increased heat rejection

from it. Once you have the case temp down to within a degree or so of the exterior ambient, increasing the

airflow through it doesn't do much but create more noise.

 

[PhoenixOfWater]

THUGSROOK-Nice case! Did you do it yourself?

 

[THUGSROOK]

the 3 120s were precut (frozencpu.com).
i cut the 2 60s in the front (its the angle, they look better then that!)
and have since trimmed out the front and rear 80mm openings so i could use regular grilles.
i also taped up every single opening in the case i could, so it wont draw air in from places i dont want it too.



dont take that wrong - you cant see any of the tape

 

[kursplat]

With a decent HSF and moderate airflow, you have pretty much what you are going to get with air cooling.

'bout says it all. the other cosideration is with positive presure your dictating where the air comes from,( i.e. through a filter) with negative presure it's being drawn in from all the little opening all over your case.

 

[THUGSROOK]

i agree - i had way too much cooling.

but maybe the intake openings in the side panel, helped make a difference?

ppl can run tests using cardboard and cut outs? ...before doing the real thing.