top blow hole

[simpleman]

dose a top blow hole do much or would it be a waste of time?
i have an antec full tower and it only has places for 4-80mm fans.
2 in the front, 1 of which is blocked by 3 hard drives, and 2 in the
rear. i have a thermalright s-947u with an 80mm tornado.
my barton 2500+ OC'd to 3200+ runs about 110f
i don't know what that is in celcius. i have a temp gauge with an under cpu sensor so i know my temps are right,
also my temps rise to 119 at full load.
are these high temps or normal, would a top blow hole help???

 

[Serraph]

I made a 120mm blowhole in my Chieftec full tower. I didn't see a single degree of difference in my cpu or case temps.
Some people say it drops their temps alot though so I don't know what to tell you. In my case it probably didn't do anything because I already had really good airflow with just the 2 front and 2 exhaust. (Idle: Case=27 C, CPU=33 C ; Load: Case=27 C, CPU = 36 C)

 

[gusgizmo]

youd get better responses if you posted your temps in celsius. anyway, yes you will get better temps with a blowhole, but you need corresponding intakes, or else you will have inefficient airflow, and negative air pressure, which causes dust to build up.

 

[clocker2]

i have a temp gauge with an under cpu sensor so i know my temps are right

I wouldn't bet the farm on that. Have you any software monitors to confirm your temps?
One easy method of estimating how effective a blowhole may be is to run the rig up to operating temp and then remove the side panel.
Stick your hand up by the roof.
Is it warmer up there than down below ( chances are excellent that it is)?
Does the machine run cooler with the sidepanel off?

If you answer yes to both then a roofvent ( maybe without a fan) will help.
Why fight thermodynamics?
Let convection work for you...

 

[linlibj]

Leave your antec full tower alone. You don't need a blow hole for this case. Mine is Chieftec full tower, which is almost exactly like your antec. With 4 80mm fans, my 2.66G P4 under full load has 40C reading. I have Alfha 8945(?) HS, which is much much better than Zalman7000 Copper.

 

[felinusz]

I have the same case, in the Chieftec Dragon flavour.

This case is set up so that the PSU is mounted sideways way up at the top of the case, quite far from the rest o the system.

In doing tests with my case, I have discovered that the case ceiling is an *INCREDIBLE* hot-air trap, and I mean really, really warm compared to the rest of the case - from the PSU heat buildup by my best guess.

I am adding a silent 120mm fan (a 120mm Evercool Aluminum running on 7V - powerful, and totally silent) blowhole to my case, right above the PSU. This won't help my CPU temperatures at all, seeing as how far away all this hot-air is from the Processor - and considering that there ar two exhausts right by the CPU socket anyways. But, it will give me peace of mind that there isn't a huge dead-zone of hot air building up in the roof of my case, and making my powersupply heat up.

Negative pressure is not an issue, due to 3 120mm intakes, and an 80mm intake.

 

[simpleman]

well i would post temps in celcius but the temp gauge i got was faren.
i have a sensor at top of case also and it's only 80 f.
i removed me side panel and my temp droped on average of 7 degrees f. and the top of case is cool.

 

[clocker2]

Well if removing your sidepanel lowered the temps by seven degrees then obviously your current setup is doing a insufficient job of evacuating heat from the case.
Hot air rises.
Logic would dictate that a blowhole would be a good first step.

The problem with having to experiment with aircooling solutions is that at some point you have to start making irreversable alterations. Once you cut a roofvent, you're stuck with it.
No going back.

So I guess that now your first decision is how far you are willing to go for uncertain results.
It's a crap shoot and your virgin case is what you have to ante up.

 

[simpleman]

oh it's not a virgin case at all i just got it done and up and running
i could mod a fan in there i guess the question is what size fan to start with?

if i am going to do more cutting on it i'll do a blow hole so it will fit the mod and if it don't help i can always make another window

 

[clocker2]

Well alrighty then.
My recommendation would be to size the blowhole to accept a 120mm fan.
Drill all the mounting holes and then install one of those wire mesh fan grills to start.
It's possible that the air will exit all by itself and your temps will drop.
Then you can add a fan and see if there is a significant improvement.

 

[simpleman]

i am gonna try that thanks for the input

 

[crull]

I made a 120mm blowhole in my Chieftec full tower. I didn't see a single degree of difference in my cpu or case temps.
Some people say it drops their temps alot though so I don't know what to tell you. In my case it probably didn't do anything because I already had really good airflow with just the 2 front and 2 exhaust. (Idle: Case=27 C, CPU=33 C ; Load: Case=27 C, CPU = 36 C)

I also didn't notice any improvement with the 80mm blow hole I put in my case. I was running a fan and that didn't do anything with temps. The fan died so I just have the hole with just a grill. If I put my hand over the hole I can feel warm air rising out of the hole, but it doesn't seem to lower case temps at all. My case temps were usually pretty good before adding the hole so maybe thats why. I think its a good idea though even if it doesn't help with case temps, because it lets out the hot air from the PS and any thing else close to the top of the case.

 

[clocker2]

Maybe if you guys who put in a roof vent but didn't see a improvement flipped your rear exhaust fans and made them intakes you'd have enough positive case pressure to push some of the warm air up and out the top...
Not terribly hard to try, what have you got to lose?

 

[specific]

flipping your rear 80mm fans would also feed cooler ambient air to your cpu, and a 120mm exhaust on top would be appropriate. The only thing to watch out for in this case would be your psu exhaust. A simple duct directed upward would keep this warm air from re-entering your case via your rear 80's.

another route....... duct the air coming out of your heatsink fins to the exhaust fans. and/or drill some holes in your window to duct outside air straight to your cpu fan. these may be hard to pull off while keeping close to the color scheme you have there.

What matters most here is the effect on cpu temps. Case readings may or may not change, depending on the placement of said diode/temp probe.

 

[Serraph]

...turn the exhaust fans into intakes? That's INSANITY!

Lol j/k. I'll give it a try when I get back to my apartment (at home for the holidays). It sounds like it could work though.

 

[specific]

Think about it.

More cool ambient room air coming in. The only place it can go is out of the one very efficient 120mm exhaust. The positive case pressure will force more air through the heatsink. If you use filters on your intakes, less dust. This is a win-win situation.

 

[crull]

Maybe if you guys who put in a roof vent but didn't see a improvement flipped your rear exhaust fans and made them intakes you'd have enough positive case pressure to push some of the warm air up and out the top...
Not terribly hard to try, what have you got to lose?

I can feel a little bit of air rising out of the top hole. I also have enough intake fans. 3 Side 80mm's and 1 front 80mm's Also the cfms for intake is quite a bit higher then the exhaust cfm's.

In my case it's a pain to flip the fan around. I have the ATX power cable and 12 Aux Cable tied to it with zip ties all nice and neat, and the cables from the fan zipped nice and neat to the bottom of the supply.