Should rear case fan be outtake?... I'm thinking of making it intake

[EstoyLoco]

Right now I have the case set up with:
2 front intake fans
1 rear outtake fane
2 fans in PSU (1 rear outtake, and bottom of PSU intake fan)

I only have 1 AGP vid card on the MB, and that is below the rear outtake fan.
When I put my hand near the rear outtake fan... it is very cool,
When I put my hand near the rear PSU outtake, it is very warm.

My motherboard is layouted such that the CPU is right below the intake fan of the PSU, so any heat come the CPU gets taken out immediately.
My CPU runs at about 55 deg under heavy load.

Now I was wondering, should I make the rear fan an intake one instead of an outtake?

 

[deadseasquirrel]

outtakes are what they show over the credits on the Cannonball Run movies.

you should keep the rear fan an exhaust fan to ensure proper airflow through the case. if it was to intake, it'd be intaking A LOT of the very hot air the PSU fan blows out (considering it probably sits very close).

 

[beatle]

I tried this and temps actually went up. I think they would also go up in your case (no pun intended ). It's important to have a balance of air going in and out of the case. The PSU may have 2 fans, but only one outlet, so count that as one fan.

You might try one of these if you are seriously considering bringing in air from your rear fan. Or possibly fab one up with parts from Home Depot.

 

[daniel1113]

I was just checking out the Overclocker's Cooler Kit and was wondering how it would connect to a heatsink such as an SLK-900. I can't really tell from the pictures. Thanks.

 

[EstoyLoco]

great points there.. i hadn't considered that it would draw the hot air from the PSU back in...

 

[EeyoreX]

I don't know how much of the air exhausted by the PSU fan would really be drawn back in if you were to reverse the rear fan. Heat rises so the warmer air should not really be "sinking" to the level of the rear fan below the PSU fan. This of course does depend somewhat on the area behind your case. If its enclosed in a cabinet or there is something blocking the air from rising, that may cause a problem. I plan on trying this as well, as I have seen cases where it has lowered temps and others where it has raised them. My case currently has only 2 intakes in the lower front, but a total of 4 exhaust (most or which remain off most times) I have the PSU exhaust, two exhaust under the PSU fan and a top blowhole. When I get around to it (it's such trauma to turn my PC off ) I plan on trying at least one of the two rear exhaust (the lower one) to an intake and see what happens.

Really, it depends on so many variables the single best way would be to try it both ways and see what happens.

\Dan

 

[EstoyLoco]

I still plan on testing it...

I first thought of this idea... because the rear fan just seemed way too exceptionally cool...
It seemed like it was actually just taking the air from the front and immediately sending it out the back, without actually cooling anything...

So i figured if i reversed the rear it might, force air to pass the CPU on go out only thru the PSU

 

[0roo0roo]

read side column http://www.dansdata.com/hx45fan.htm

 

[Sid59]

i think it also depends on how close the rear of your comp is to a wall. if it's pretty close then there's no air BUT THE EXHAUST OF THE PSU gonna be intaked into your rig.

 

[Zepper]

I would suggest that your PSU fan is running too slowly. Perhaps you need to cut it loose from the internal thermal fan speed controller (which may not be working properly) and put it on a manual control like a rheostat (100 ohms works well for most 12v fans) - just set the rheostat for the best balance of cooling and noise. You might also consider putting a heavier duty fan in the PSU (the built-in ones are usually cheap) - you can even get them with a rheostat kit included.
. Generally, the intake fan(s) should be as low in the case as possible. If you need to add an extra intake, mount it near the bottom of the side door or even in the bottom of the case (don't forget a filter!) - I've actually put legs or rails on the bottom of cases to raise them up enough to mount a fan on the outside of the bottom (can be tricked out to look like a rocket or flying saucer engine - think neon ring fan guard on a chrome or clear LED fan). If you need extra exhaust, a top blow-hole would be best. You can also get duct kits from svc.com (as well as most of the other goodies I've mentioned) that will allow you to bring cool outside air directly to the cpu heatsink and the clever can imagine other uses for it - they even come with a chimney for the PSU fan to avoid sucking warm exhaust air back in.
. That should be a good number of ideas for you to work from ...
.bh.

 

[lenjack]

Try it both ways...nothing to lose. I did and found my temps to be lower with rear fan on exhaust.