# Negative Pressure - no intake fans



## Kammster (May 20, 2007)

How it works: 
CPU : intake funnel + amd fan + 80mm exhaust (restricted vent holes) (31 deg idle)
Gfx : side panel intake vents + zalman + 60mm exhaust (39 deg idle)
PSu exhasut + intake vents in front of hardrive (32 deg idle)
chiptset 34deg (idle)



I just wanted to exhuast the hot air from the case before it statred to effect the generic psu, so i cut a hole in the thin sheet metal, and installed a 60mm fan for testing and i got a big surprise!
not only did hot air vent out faster but the other components got as much as 5 deg cooler.

before chipset hit: 43 deg under gfx card heat
after : 38 deg / 39 deg(silent)

the temp drop was also on the cpu load temp 42 to 39
but the gfx card was best; before my max temp never varied with clock frequency always 63 deg.
now 300:350 (barely 54 deg); 415:496 (59/60 deg)


my theory is: basic fliud mechanics volume in = volume out. the exhaust fans pull so much air out of the case that they not only pull in air thru the vents but also cause air in the case (hot air) to move in currents to the exhausts(2+psu). 


i am 60mm(25mm thick) 12v@0.12V thta i got from a car parts store.
also tried a spare fan from a mircofin socket A cooler: 
dynatron mircofin (15mm thick) 12v@0.25v top speed 5200 rpm (loud -48 db), i forgot the temps because it was too loud, @silent(5v) was same.


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## ex_reven (May 20, 2007)

The only downfall is you get more dust in your case


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## Kammster (May 31, 2007)

*quick update*

there is dust everywhere, any place than air can move there is dust, behind the hard drive the front grill thing has dust spikes like a fan blow it there.

had to  take out the 80mm fan for another case, put in a 92mm and it really kicks
temps gpu @ 400:425    57core:45mem
and the temp falls fast when the load stops.

vibration from the fan on side panel was bad but got a idea from a generator room and used rubber strips for patching bicycles to dampen the noise.


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## [I.R.A]_FBi (May 31, 2007)

actually positive pressure is more desired than negative ...


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## kwchang007 (May 31, 2007)

[I.R.A]_FBi said:


> actually positive pressure is more desired than negative ...



really? so air just starts flowing out type stuff?

EDIT:  I always though balanced pressure was the best?


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## Zeratul_uy (May 31, 2007)

kwchang007 said:


> really? so air just starts flowing out type stuff?
> 
> EDIT:  I always though balanced pressure was the best?



I got intake front, exhaust rear... That's the best setup i've tryed so far and works preety well.

Let´s see if i find some pic with my temps before my mobo dies...


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## Zeratul_uy (May 31, 2007)

Found it, Everest Temps right there, and Shitty BG with my name xD 





Black = HD
Blue = GPU
Brown = CPU
Green = Mobo

And those aren't my best temps  coz that ones was after running the bench xD
Best Idle were 25 HD, 20 GPU, 26 CPU and 19 Mobo...
Believe it or not 

See'yas!


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## kwchang007 (May 31, 2007)

Zeratul_uy said:


> Found it, Everest Temps right there, and Shitty BG with my name xD
> 
> 
> 
> ...



i believe you.  my friend is running his e6600 with stock cooling and thermal paste, and it idles around 28 when it was ~65 F.  he has one intake on the front, one intake (cpu sleeve thing) one side, one exhust on side, one exhust on back, and the psu.  very cool system, you can feel the room heat up (i guess that's not a good thing, lol) sounds kinda like a turbine when it's running though....in a good sort of way.


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## Kursah (May 31, 2007)

[I.R.A]_FBi said:


> actually positive pressure is more desired than negative ...



From my experience and a few of my IT buddies, they find a close match to a 1:1 ratio serves well, you have your exhausts up high and rear, intakes low and front, it helps replenish the exuasted hot air faster with cooler air than negative, since you have fans pumping air in. Posotive I believe would be more intake than exhaust, which is the least effecient method, it will not be able to remove the heat as quickly, which is the goal with OC'd PCs. If you have more air moving in the case, but not exhuasting hot air efficiently, you're trying to cool your components with hot air, doesn't make much sense, but posotive is supposedly the best way to keep dust to a minimum. I'd rather clean my PC more often and get more effective cooling. I may be backwards on those, but that's how I understood it. 

Also, IRA, you gonna fill out your system specs in your User CP so we can see whatcha got running? I'm kind of curious, because it seems like you have some OC experience. Let's see what you have.


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## [I.R.A]_FBi (May 31, 2007)

pc is currently down .. waiting on a vid card .. got a E6400 ... 2 gigs o ram, ABit AB9Pro, stock intel cooler for now


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## Kursah (Jun 1, 2007)

Nice, keep us posted on how it turns out!


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## Zeratul_uy (Jun 1, 2007)

kwchang007 said:


> i believe you.  my friend is running his e6600 with stock cooling and thermal paste, and it idles around 28 when it was ~65 F.  he has one intake on the front, one intake (cpu sleeve thing) one side, one exhust on side, one exhust on back, and the psu.  very cool system, you can feel the room heat up (i guess that's not a good thing, lol) sounds kinda like a turbine when it's running though....in a good sort of way.



Hahaha, mine is not sooo noisy, tested just all the fans, with the case empty cry: there is nothing in there) at 5 am, when the house is ultra silent and the only fan that made a noise, was lubricated and now is not noisy xD Ultra Silent Zera Cooling lol \o/


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## kwchang007 (Jun 1, 2007)

Zeratul_uy said:


> Hahaha, mine is not sooo noisy, tested just all the fans, with the case empty cry: there is nothing in there) at 5 am, when the house is ultra silent and the only fan that made a noise, was lubricated and now is not noisy xD Ultra Silent Zera Cooling lol \o/



lucky you, his sounds like a turbine when he starts it up pheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeewwwwwww but it does a good job at keeping it cool.  and if he bought a fan controler, im sure he could leave them all at low and still get really good idle temps.


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## Zeratul_uy (Jun 1, 2007)

kwchang007 said:


> lucky you, his sounds like a turbine when he starts it up pheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeewwwwwww but it does a good job at keeping it cool.  and if he bought a fan controler, im sure he could leave them all at low and still get really good idle temps.



Hahahaha, he need limits on those rotations xD hahaha the "phewww" thing was really funny hahaha


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## kwchang007 (Jun 1, 2007)

Zeratul_uy said:


> Hahahaha, he need limits on those rotations xD hahaha the "phewww" thing was really funny hahaha



lol thank you.  he sort of does....i mean he's usally blasting music, or playing his guitar really loud....so the pheww isn't noticable.  actually now that i try and remember, once it's running, you don't really notice it, it's just when you start it and it goes phewww, here's the case


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## Zeratul_uy (Jun 1, 2007)

kwchang007 said:


> lol thank you.  he sort of does....i mean he's usally blasting music, or playing his guitar really loud....so the pheww isn't noticable.  actually now that i try and remember, once it's running, you don't really notice it, it's just when you start it and it goes phewww, here's the case




Looks really sexy, mine is self-made hehe i cutted, drilled and tweaked myself... I'll upload some pics 

And for the noise thing, my Heatsink used to do tons of noise too lol it wasn't "phewww" it was like "hhhhhhhhhhhhheeeeeeeeee" and was really annoying coz I couldn't hear at low volume xD and when the night is silent, arround 3~5 hs am, it was really unbearable... So I've reduced the RPM's of it and it worked still at good temps and ofc with much less noise... 
(Taken with a webcam, my digicam is broken)
Before painting and mounting of the side Metacrylate (dun remember if it is spelled right) panel 





After painting and mounting of the side Metacrylate pannel and before the lights and side 120 mm x 120 mm fans \o/
Front





Rear





Metacrylate side





And the other side (nothing special on it at the pic, made an AMD logo with vinyl on it)





When I got my digicam working I'll post it on rate my case, now it's finished xD


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## kwchang007 (Jun 1, 2007)

Zeratul_uy said:


> Looks really sexy, mine is self-made hehe i cutted, drilled and tweaked myself... I'll upload some pics
> 
> And for the noise thing, my Heatsink used to do tons of noise too lol it wasn't "phewww" it was like "hhhhhhhhhhhhheeeeeeeeee" and was really annoying coz I couldn't hear at low volume xD and when the night is silent, arround 3~5 hs am, it was really unbearable... So I've reduced the RPM's of it and it worked still at good temps and ofc with much less noise...
> (Taken with a webcam, my digicam is broken)
> ...



yeah, it's sexy, just no side panel, and i don't think he wants to mod it (he's not even overclocking ).  you have no idea how many cases we had to go through....it'd be like ....too blue....not blue enough....not enough fans.....to white (some weird stuff) but now....sexiness.  wow, nice case.  id defiantly give you a good rating (as long as you have good cable mangment, etc, the case is nice though)


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## Zeratul_uy (Jun 1, 2007)

kwchang007 said:


> yeah, it's sexy, just no side panel, and i don't think he wants to mod it (he's not even overclocking ).  you have no idea how many cases we had to go through....it'd be like ....too blue....not blue enough....not enough fans.....to white (some weird stuff) but now....sexiness.  wow, nice case.  id defiantly give you a good rating (as long as you have good cable mangment, etc, the case is nice though)



Pics are way crappy, the cables were tied and moved away to let space for airflow, but now (before I taked all off) they were covered with a green (dunno how to say it lol) hmm thing xD  and some green lights... It was nice...


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## kwchang007 (Jun 1, 2007)

Zeratul_uy said:


> Pics are way crappy, the cables were tied and moved away to let space for airflow, but now (before I taked all off) they were covered with a green (dunno how to say it lol) hmm thing xD  and some green lights... It was nice...



green!!!  a much different color than the normal blue.....i think i like green.....hmmm...actually, i think i like no lights and a slient computer so i can sleep with it on, of course since slient is not possible....LIGHT IT UP!


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## Zeratul_uy (Jun 1, 2007)

kwchang007 said:


> green!!!  a much different color than the normal blue.....i think i like green.....hmmm...actually, i think i like no lights and a slient computer so i can sleep with it on, of course since slient is not possible....LIGHT IT UP!



It was everything black (Mate? it's ok?) but painted the inside of fluo green, and with the lights it rox ^^
Personally, I love black mate and fluo green \o/


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## kwchang007 (Jun 1, 2007)

Zeratul_uy said:


> It was everything black (Mate? it's ok?) but painted the inside of fluo green, and with the lights it rox ^^
> Personally, I love black mate and fluo green \o/



lol i meant lights when i said green.  just cause...well....idk maybe it's because our grass is dying.  i think it'd be intresting to see something with a UV light, are there any case mods here that have a UV lighting?


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## Zeratul_uy (Jun 1, 2007)

kwchang007 said:


> lol i meant lights when i said green.  just cause...well....idk maybe it's because our grass is dying.  i think it'd be intresting to see something with a UV light, are there any case mods here that have a UV lighting?



I could change the green lights by UV lights... If you rate me 10/10!! haha 
Already though it but preffered green ones, I can give a try


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## [I.R.A]_FBi (Jun 1, 2007)

kwchang007 said:


> really? so air just starts flowing out type stuff?
> 
> EDIT:  I always though balanced pressure was the best?




from the Ideal Gas Law , pV=nRT. Rearranging we get n=(pV)/(RT), so increasing the pressure increases the number of air molecules to conduct away heat.

im just theorizing still ...

Bless


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## Kursah (Jun 1, 2007)

I tested the positive air induction method, my temps increased by quite a few degrees C. The Ideal Gas Law makes sense, but at least in my application using More CFM Out than In (not by too much, based on est. fan airflow from specs) was the coolest airflow based solution. But if a few people try removing their case exhaust fan and only using PSU fan for exhaust, leaving intake installed and running, compare to current temps. That's the best way to verify is to try it out and see results with your own eyes. 

IRA, you have any goals set for OC-ing that 6400?


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## [I.R.A]_FBi (Jun 1, 2007)

yeah, i dont want to burn it up, lol. i live ina tropical country so 2.8 - 3.0 will do ... or 3.2 when im going to go crazy. i got a freezer 7 on the way still


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## Zeratul_uy (Jun 1, 2007)

[I.R.A]_FBi said:


> yeah, i dont want to burn it up, lol. i live ina tropical country so 2.8 - 3.0 will do ... or 3.2 when im going to go crazy. i got a freezer 7 on the way still



Based on all the cooling tests I've done on my case, i think that one side intake and other side exhaust is the best, air pass thru, taking fresh air and removing hot one... 
Dunno, my best temps, under Everest and SpeedFan are that way. I've got like 20 degrees down that way hehe...


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## [I.R.A]_FBi (Jun 1, 2007)

case currently has 2 120's and one 80 blowing in and 2  800's and the PSU 120 blowing out


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## Kammster (Jun 1, 2007)

my thing works for me because of my "small case" the x800 is a long as the board so it almost splits the case in two sections and with the fans and intake vents so close it works better and opening the side panel.
it like in the movies when the submarine under water has a hole the water rushes in. the water outside has more pressure than the air in side.

in a spacious case i don't know how it would work.


In my old case (modding now) , a biostar barebone the power supply was infron to of the cpu and the it got very hot, by sucking back its hot air into the heatsink. i pasted a fan on to the roof to blow the air away but, the hot air went down on to video card and board. i had to put in another fan to blow the air out the pci slots.


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## Kammster (Aug 4, 2007)

*more messing around*

i wanted more silence, basically idle temps are up but max temps are same or lower

Enlarged the hole for a 80mm fan, quiet and no vibrations
got the coolermaster with a 120mm fan (noisy soon to be replaced)
vf700 connected to x800 pcb for the fan control.
replaced amd 60mm stock fan with 80mm quiet fan.
put 92mm fan on 5v


dropping the speed of the zalman fan make the temp on chipset drop 4 deg. chipset is always at 34 deg now. the zalman fan never goes over 67%, running on full 12v is like a waste of power.
control the hot air even if it means slowing a fan down.


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