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Help my case has no Pressure

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August 9, 2009 4:41:57 AM

Ive been busy installing components I forgot I should have my case pressurized in some way. Well my case is just like this ( http://c1.neweggimages.com/NeweggImage/productimage/11-... ) and as of now I have three fans plus two component fans (gpu and psu). Well Its been getting hot outside and lately when i get into an intense gaming session i notice the gpu begins to cook my foot. So I think I might have an airflow issue and need some help figuring out which setup will work best for my case.

Right now I have the front and one side hole as intake while the back hole is exhaust, the other side hole is empty. The gpu exhausts air with a ~80mm fan while the psu also exhausts air but with a 120mm fan ran at an automated slow ass speed.

Ive also read up on keeping it pressurized but couldnt find a solid answer on which is better between Negetive and Positive pressure. Right now with that open side hole and all my metal bays in the back popped out im very sure im lacking in the pressure catagory. LoL

So any help you can give me with fan direction/optimization along with Pressure information would be much appriciated. Thank you :hello: 

More about : case pressure

August 9, 2009 12:13:16 PM

does your psu have a fan blowing down on to your cpu cooler? if not, I always perefer to have my back fan blowing cool air over the cpu and pci components then having exhaust out of the front, this stops hot air getting trapped behind the pc.

Its all a bit of trial and error though, you might find that an inblowing fan on the back just recycles the exhaust from your GPU back into the case and makes things worse.... just depends on your envoronment and case position.....

The other option is watercooling, there are some fairly decent prebuilt kits these days, then all you have to worry about is the airflow over one radiator.

August 10, 2009 5:12:43 AM

Normally the air flow is front and side fans blow cool air into the case and the rear and top fans blow the hot air out. With some good cable management, there should be enough space in side the case so that the cool air blows over everything without being blocked by all the PSU cables.

Also, I would get the blank metal bays and block up those open slots as you would have no idea if hot air is passing in or out through them. Better to have them blocked so that you have an idea of how air is flowing through your case.
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a b ) Power supply
August 10, 2009 1:00:16 PM

Whether a case should have positive or negative pressure inside seems to be a matter of opinion, with almost nobody providing facts based on controlled experiments - and that includes me. I prefer positive pressure inside, as you do.

In one forum here a poster had a really good way to check. Light an incense stick, but don't bother with the chants. Move the stick around the case and observe whether the smoke flows into the case or out. Allowing for the known points around fans, etc, concentrate on the air leak spots. While you're working on this, check and make sure all your air intake dust filters are clean.

If you decide you need more air inflow, you have the obvious choice of adding a second side fan.

Don't forget that the purpose of all this is not to ensure high air flow or positive pressure. It is to ensure the CPU and GPU run at acceptably cool temperatures. Even the high heat output of your video card is not necessarily a problem. Maybe that just means the fans are all working and all the heat generated there (it can be a lot!) actually is being removed from the case.
August 10, 2009 6:15:39 PM

Thanks for all your help guys, from all the information I think i need to plug up some leaks and atleast get some pressure going. One more question though, is it possible to have too much pressure, possably damage the other fan cooled components?

The reason I ask is becasue I think im going to take that back fan and flip it for intake on the side. But then that makes 3 (really powerfull) intake fans versus my moderate gpu and slow psu exhaust fans. Will that damage anything? Do you think i should leave that back hole open to exhaust air out?

Thanks again.
August 10, 2009 6:19:08 PM

Paperdoc's answer is pretty comprehensive here. Personally, I don't think "pressure" is an issue. As long as there is a decent amount of air coming one end and going out the other, and that airflow goes over your components, you're good.

1) If you have fans at the front, back and side, I would make sure your front fan is
taking air in and the back is blowing it out. I would personally have the side fans taking air in. If they're adjustable, turning them all the way up never hurts!

2) Remember that with all these fans, you need space around your pc. It isn't going to help if, as will_chellam says, there is hot air building up behind it.

3) You've got a lot of empty bays. Mind if I ask how dusty it is in there? A bit of a spring clean inside the case may be in order. Than cover up those holes. You're trying to crate a little weather system here, and unless you have a fan pushing the air in, these might not be helping!

4) You haven't mentioned your components, temps, or any overclocks you might have. What are they? You might find the GPU is doing what it is normally expected to. I run a 4870, and the normal temps for that scare me. But it's a hot card, and is to be expected. use a program like Everest, Core Temp or Real Temp and compare with verious things online.

5) What CPU fan do you have? If it's an intel stock, this is less of an issue. But if you're using something like the Arctic Freezer 7 Pro, make sure the fan is at the front, so it's taking air in from the front and pushing it towards the exhaust fan at the back of the case.

6) Don't live somewhere hot. Guess there's not too much to be done about this one!
August 10, 2009 6:22:31 PM

I'd say don't flip the fan. You would be drawing a lot of air in, heating it up with the components, and then giving it nowhere to get out. You cann swap the airflow so it is back to front if you like, but you do need it to flow.
a b ) Power supply
August 10, 2009 6:22:37 PM

It's a lot less about pressure and a lot more about airflow. If you have large openings, you can get a lot of airflow without very much pressure. You typically get the lowest temperatures with the side of the case off completely, which means NO pressure differential but a very LARGE opening.

The proof of the pudding is in the temperature readings you get from programs like HWMonitor. If your readings are too high, you need to do one or both of the following:

a) Increase the airflow by increasing fan speeds and/or providing more fans and intake/exhaust ports, or

b) Make sure that the cool intake air is getting distributed to the right parts of the interior of your case. That might mean rerouting any cables that block the airflow or using internal fans or baffles to direct the airflow where you want it.
August 11, 2009 3:30:50 PM

Hello again, now my tempetures havnt been as high but also it hasnt been as hot. anyway I flipped that back fan to intake and put it on the side so now I have 2 intakes on the side blowing onto the gpu, but also if you've seen the geforce gtx260 its enclosed in a case like body, so how much are these fans really helping it?

Secondaly with all the holes closed up I can feel the positive pressure when I open one and put my hand infront of it.. which brings up the question do you think if I leave the card bays open it will help air exhaust out from the graphics card? or would I be losing to much overall pressure.

Here are some more specifications.

intel duel core 3.0ghz, stock heatsink
geforce gtx 260
corsair tx750w <--- slow ass fan!
4 ram sticks with stock heat spreaders

The only thing ive been watching was the graphics card, it seems to get more hot then my power supply despite how slow the psu fan is.


Geforce gtx260, *celcius
-Idle ~ 41*
-Moderate ~ 50
-Heavy ~ 59* - 65*

Fans:
Geforce gtx260 exhaust
Corsair tx750w exhaust
Three 80mm fans for intake ( http://www.newegg.com/Product/Product.aspx?Item=N82E168... )

I was experimenting with it, it seems like that extra fan on the side does help cool down the gpu slightly. Ive been giving it much thought and im wondering what if I left all 3 fans on intake and got a 120mm fan (using a 120mm to 80mm slot convertor) and use that 120mm as exhaust in the back of the case? That way its less of a pressure situation and more of airflow, fresh air from the front and sides, hot air exspelled from the rear.

Or is that just overkill? Tell me what you think, I probably dont need a fan in front for my one lonely harddrive but the two intake fans on the side are a great idea for my gpu other then that im not sure what to do with the back.
a b ) Power supply
August 11, 2009 6:15:45 PM

dltreetech09 said:
...im wondering what if I left all 3 fans on intake and got a 120mm fan (using a 120mm to 80mm slot convertor) and use that 120mm as exhaust in the back of the case? That way its less of a pressure situation and more of airflow, fresh air from the front and sides, hot air exspelled from the rear.
Exactly. Again, it's not about pressure, it's about airflow. You can maximize pressure by putting a fan on every opening and having them all try to blow air into the case - but you're not going to get any airflow and your temperatures will go off the scale...
!