I am building my first computer and have read a little about pos. and neg. pressure in a case. while there are advantages to both, it seems that negative pressure cools better. any thoughts on this?
BTW i was thinking of going with two 120mm fans and two 80mm fans in this case

Positive + airfilters = clean case, any negative pressure results in regular disassembly for dust bunny hunting.

i've been told that equal is the best way to go...the only thing i suggest is that you try to keep it semi even... also i have noticed that side fans are TOTALLy worth it...especially in smaller cases... in addition...exhaust fans are not to be overlooked...they MUST be utilized because that is where the hottest air is...and it needs to escape some how

Quote: Originally Posted by WuGgaRoO i've been told that equal is the best way to go...the only thing i suggest is that you try to keep it semi even... also i have noticed that side fans are TOTALLy worth it...especially in smaller cases... in addition...exhaust fans are not to be overlooked...they MUST be utilized because that is where the hottest air is...and it needs to escape some how

I agree. In all my computers I use equal pressure. You are supposed to have the same amount coming in that is going out. This prevents any fans from being overworked, or air coming in through every crack in the case.

on my Athlon XP PC with a window of fans, i use negative pressure this allows every tiny spot to have a vaccum like flow over it, and with the smal cracks and all the fans filtered there isnt any problems with dust or keeping things cool, the ambient temps internal are around 28-30C depending on the room temp

for my sempron i used negative as well having one high CFM fan intake and 3 exhaust fans two on top, one on back then the flow cam in and out perfectly and with a filter on the only intake fan, dust free as well

but equal has been said to be best for the most part, but ive never had a fan die on me, ever, well with the exception of dropping it while it was running and cracking three blades off (high speed 7 blade) but i got it replaced by the manufactuer for free

It actually depends upon the location of your components and the type of heatsink you are using. I've mentioned before about the "stealing air" factor when you have a heatsink near your exhaust fans. Even the PSU can steal air if it has a high flow intake near your CPU. If I had exhaust fans directly behind my CPU I would probably turn them around to feed air instead of take it.

Whether you go neg or pos, there is still regular maintenance that needs to get done. You just may have to do it more with more positive pressure. However, if that means my components are cooler, I'm willing to do the extra work. You would have to describe your case, fan location, and components used before we could give definitive advice about the airflow.

Quote: Originally Posted by BigAkita It actually depends upon the location of your components and the type of heatsink you are using. I've mentioned before about the "stealing air" factor when you have a heatsink near your exhaust fans. Even the PSU can steal air if it has a high flow intake near your CPU. If I had exhaust fans directly behind my CPU I would probably turn them around to feed air instead of take it. Whether you go neg or pos, there is still regular maintenance that needs to get done. You just may have to do it more with more positive pressure. However, if that means my components are cooler, I'm willing to do the extra work. You would have to describe your case, fan location, and components used before we could give definitive advice about the airflow.

You have a very good point, but as you said, it takes all the different information to provide the best pressure for you, and in most cases, you just dont want a large difference, like 50-100 in and 300-400 out, or the opposite just so the mosdt needed components get there fresh air, and the air has somewhere to go

the fan window on my case has a intake right infront of my CPU coolers intake, and another beside it from the back fan, but the two fans on the right side of the door are exhaust, along with the PSU and front bay fan(80mm) the best way to cool a CPU is to bring the most outside air in, cause case temps tend to be warmer than room temps, this is why my negative pressure works for me

I haven't got any components in the case yet, actually the case isn't even here yet. Scheduled for delivery monday. Here is what it looks like. It comes with two 80mm fans on the top and window. I have two logisys 120 mm fans that im going to put in there aswell. So one 120 and one 80 in and one 120 and one 80 out should create equal pressure. So i guess my ? is do you have any suggestions on where to place the in and the out fans?? Thanks guys for your help

I actually built a computer for a friend with that exact same case. I took the time to cut out the built in fan grills, and the temps seemed pretty good. Also I loved the UV reactive acrylic it uses. However, I had constant problems with the LCD display. It would not keep the time no matter what I tried. I replaced the battery and all, but no go. Hopefully you have beter luck with the case!

Quote: Originally Posted by Sn0wMan I actually built a computer for a friend with that exact same case. I took the time to cut out the built in fan grills, and the temps seemed pretty good. Also I loved the UV reactive acrylic it uses. However, I had constant problems with the LCD display. It would not keep the time no matter what I tried. I replaced the battery and all, but no go. Hopefully you have beter luck with the case!

What are your thoughts on that case?
man, bummer about the lcd - wish i would of known that before i got it ohwell....
as long as it displays all vitals. Yeah i was looking at those little holes they call a fan grill - def have to go.
do you think its necessary to put fan filters on the exhaust fans?

Quote: Originally Posted by OCBeats What are your thoughts on that case? man, bummer about the lcd - wish i would of known that before i got it ohwell.... as long as it displays all vitals. Yeah i was looking at those little holes they call a fan grill - def have to go. do you think its necessary to put fan filters on the exhaust fans?

No i dont think you needto filter any dirt that nay blow out of your case, but if you go with negative pressure make sure any holes are covered with a filter or tape or something so no dust gets sucked though, but exhaust fans you usuallywant tobe open and able to blow dust out

Well, i've heard this argument many times before. In my case, i have a silverstone 120mm variable fan for exhaust and 2 80mm 30cfm fans for intake. So, i have equal pressure if i put my exhaust to 60, which isn't it's highest speed. I notice better cooling when i'm close to equal, and when i put the fan all the way up, i don't notice any difference from equal, since then it goes to negative. I think equal pressure is best.

Just an FYI - I have two 92mm front intakes and two 120mm exhausts. I have a second pair of 92's set up in a dual fan config to increase intake to equalize things a bit. I was really suprised that when I took of the side panel, the intake fans were really blowing! Felt like a table top fan. I figured I had created a really huge positive pressure with the two low speed 120mm exhaust fans and the now FOUR 92mm intakes. This weekend I was measuring some cool looking fabric and pulled the side panel and laid the fabric over the opening. It was alomost instantly sucked into the case. There was a tremendous amount of negative pressure that I would have never guessed about. The 120's realy fooled me. Low speed or not, they suck! Litterally. It really does an outstanding job of exhaust. You might try a peice of fabric to check your case pressures. Quick and simple way to check.

Imho... tried both.. and "in an un-scientific-way" I did not notice much dfifference....


But... I AM a fan of the "decoupled" fitting of fans... (rubber washers, mounters & silicone frames)....
Those reduce the amount of vibration " passed on" to the chassis....

Next thing I like is "unrestricted" fan intake & exhaust.. this sure benefits cooling &
reduces turbulence.. & thus noise..... " dremel time!)....

Hope this helps..

TDR

I'm a big fan of trying to create a equal pressure case. I think it promotes
a constant airflow across your components if your fans are located pro-
perly. Most unequal pressure cases tend to create hot air pockets. While
they may seem to work great, they often lead to unexplained hardware
failures. In my opinion :-)
And not all fans are created equal. Measure your intakes and exhausts
by the listed cfm's of each fan. Not by fan size :-)

Damn Girl! I'm going to measure the output of all my fans right now!

Quote: Originally Posted by unit505 Damn Girl! I'm going to measure the output of all my fans right now!

Ahahaha. PWNED!

should i get a fan controller or should i let my computer control the temp??

I can't get equal pressure in my Cooler Master 830 case, so I have 6 120mm intakes, a 120mm top exhaust along with the PSU exhaust. I must say that temps are nice. Luckily, I have a Hoover vacuum with a killer blower option to clean it out once in a while.

Many new cases are coming with vents, mesh, and louvers that won't allow you to equalize pressure. If you can't make it equal, overpower it.

Quote: Originally Posted by OCBeats should i get a fan controller or should i let my computer control the temp??

I'd go for the Fan Controller. Most Bios have a hard time telling
us the correct temp. Why trust it to control your fans :-)