Airflow

[Ages]

My case has a place for a 120mm fan in the door. Should I install one? If so, should I have it blowing air into the case or sucking air out of the case? I have a botom mounted Corsair 850 watt PSU with a large fan blowing air up from the botom of the case. See cooling system for existing fan info.

Antec 902 Mid Tower case

Cooling System
120mm Fans 1 x 120mm blue LED exhaust rear fan
2 x 120mm blue LED intake front fans
200mm Fans 1 x 200mm blue LED exhaust top fan
Physical Spec
Dimensions 19.4" x 8.6" x 18.6"


New System Build:

Motherboard: Gigabyte EP45-UD3P
CPU: E8400
Cooler: Tuniq Tower 120
Memory: 8GB DDR2 PC1100 G.Skill
HD Primary: 150GB Velociraptor
2nd HD: WD 640GB
Video Card: Saphire HD4850 1GB
Monitor: Sony Professional 19" CRT (I'll be upgrading soon)
Case: Antec 902
DVD Burner: Samsung SATA
Corsair 850 PSU

 

[ekuest]

see if you can find the cfm of each fan. that way you can add up the actual amount of air in and the amount of air out. you should have nearly even. some people like high pressure (more in than out) and some like low pressure (more out than in). the main thing is to make sure you have good flow over your hard drives, your cpu, and into your video cards intake.

 

[43st]

I think a lot depends on how much cooling you need. You seem to be going for some massive overclocking. (and the PSU is blowing out, not in)

I had a Antec 900 and only used the top 200mm with the 120mm CPU fan facing up, thru the heat sink, and into it. The case had so much ventilation that this was all that was needed to maintain 20-21C idle temps (e8500).

 

[Rifter]

why is your PSU blowing in to the case? Every one i have seen blows out.

 

[jesterb84]

Just a thought but - If you have a bottom intake fan blowing cool air up into the case, wouldn't having a exhaust fan on the side "short-circuit" the airflow? As heat rises, I would assume you would like cool air blowing into the case from the bottom and the hot air being taken out the top/top-back of the case. Personally, my decision would be to make the side door fan an intake fan (versus exhaust). Most of these side fans are positioned to blow air onto the CPU/North Bridge/GPU anyways which is a good thing.

 

[Rifter]

I agree with jesterb84 unless the PS really is blowing in because then its warm air not cool air. Then having the side fan going out would take the heat from the PS out before it gets to the CPU/northbridge.

 

[videogames101]

I would say put the sid fan on exhaust, because your gpu is heating up the air around it, and exhausting that would be a good idea. (unless you have a non-stock cooler on that hd4850 which has a rear blower....)

 

[chizow]

Originally posted by: videogames101
I would say put the sid fan on exhaust, because your gpu is heating up the air around it, and exhausting that would be a good idea. (unless you have a non-stock cooler on that hd4850 which has a rear blower....)

I'd agree with this if your gpu cooler doesn't exhaust heat. You'll see immediate drops in temperatures with a side case fan near the GPU, so if your case accomodates it, there's really no reason not to install one.

 

[Ages]

43st you are right. The fan is blowing out. I think I'm going to go ahead and install the side fan and have it blow in. That should help dissapate the heat from the video card and also blow air over the middle and lower areas of the motherboard. The psu should pull whatever hot air is left around the video card out. I've got good airflow over the hard drives and the cpu will remain cool with the tuniq tower. Thanks for your input folks, it is greatly appreciated.

 

[videogames101]

Originally posted by: Ages
43st you are right. The fan is blowing out. I think I'm going to go ahead and install the side fan and have it blow in. That should help dissapate the heat from the video card and also blow air over the middle and lower areas of the motherboard. The psu should pull whatever hot air is left around the video card out. I've got good airflow over the hard drives and the cpu will remain cool with the tuniq tower. Thanks for your input folks, it is greatly appreciated.

I'd suggest trying both directions, I can almost guarantee the PSU fan won't be exhausting enough hot air form the video cards.

 

[Ages]

The case has a large 200mm fan exhausting the top. It may be enough, I just wanted to make sure I get consistent air blowing on the mobo.

 

[43st]

Originally posted by: Ages
The case has a large 200mm fan exhausting the top. It may be enough, I just wanted to make sure I get consistent air blowing on the mobo.

This is right.. Always try to assist convection if you can. Computers have become much easier to air cool since blow holes have come into fashion. I'd never exhaust on a side fan just because it's so low in the case. I mean where do you stand in the summer time if a fan is around? Most choose to be in front of it. The only real exception is if you're trying to assist convection in the attic, or you are using a duct of some sort.

 

[videogames101]

Originally posted by: 43st

Originally posted by: Ages
The case has a large 200mm fan exhausting the top. It may be enough, I just wanted to make sure I get consistent air blowing on the mobo.

This is right.. Always try to assist convection if you can. Computers have become much easier to air cool since blow holes have come into fashion. I'd never exhaust on a side fan just because it's so low in the case. I mean where do you stand in the summer time if a fan is around? Most choose to be in front of it. The only real exception is if you're trying to assist convection in the attic, or you are using a duct of some sort.

Most aren't setting up a wind tunnel though. In a PC, you want air to come in the front and exit the rear and top. All your intake is in the front. Now your GPU fan is just blowing air onto itself, and when that air comes back around form hitting the chip, would you rather have that now hot air be forced back into the GPU, or exhausted? All your fresh air is already being provided for by your front intake fans.

 

[43st]

Originally posted by: videogames101
Most aren't setting up a wind tunnel though. In a PC, you want air to come in the front and exit the rear and top. All your intake is in the front. Now your GPU fan is just blowing air onto itself, and when that air comes back around form hitting the chip, would you rather have that now hot air be forced back into the GPU, or exhausted? All your fresh air is already being provided for by your front intake fans.

Its certainly something worth trying, you never know. I think my concern would be a turbinated effect on the hot air inside the case, rather than a defined intake and exhaust. But give both a shot and monitor your temps.

 

[zerocool84]

I have a 900 with a fan installed everywhere except the one on the HD cage. The only exhaust is the rear and the large one up top. I know for a fact my system never gets that hot.

 

[AstroGuardian]

Intake cooler!

 

[jesterb84]

To help clarify, I'm using a CM690 but airflow should be very similar to the Antec 900-series. Here is an airflow diagram from Cooler Master you can refer to - pretty useful:

http://www.coolermaster.com/Us...690-air_EN_640x480.jpg

 

[devione]

Hi all, i've been reading this thread with an interest. I've been reading up a little on SilveStone's purported "positive pressure" as well.

I have a CoolerMaster Haf 932, with a Corsair HX-1000 and a Thermalright Ultra 120 for an i7 920 which I plan to overclock soon. The cooling for my case is like this:

1x 230mm intake fan (front)
1x 230mm intake fan (top)
4x 120mm fan on side panel exhaust (side)
2x 120mm fan exhaust (bottom)
1x 120mm fan exhaust (rear)

Now, the case allows for the PSU to be mounted on the top or on the bottom. I've mounted my PSU on the top, and the PSU fan is facing DOWNWARD blowing exhaust INTO the case.

Is there anything i'm doing wrong here? I've been trying to look up information regarding optimal intake / exhaust configurations, but reading this thread and about SilverStone's "postive pressure" got me thinking. Also, pardon my lack of understanding, but it seems everyone in this thread are disagreeing with everyone else?

EDIT: the main reasons for mounting the intake / exhaust fans as above is like this: air intakes from the front / top and exits through the rear and sides. the GPUs are pointing downwards so the bottom 2 120mm fans are mounted as exhausts, while air entering the top intakes exit the rear exhaust and the side / bottom exhausts.

Am I doing anything wrong here? No offense to the OP for highjacking, but this thread (at least to me) raises more questions than answers.

 

[43st]

devione.. First off your PSU fan is exhausting (moving air out of the case), unless you've disassembled it and reversed the fan. You also have your fans directions a bit weird. It may work, but probably out of brute force, not proper design.

1x 230mm intake fan (front)
1x 230mm exhaust fan (top)
4x 120mm fan on side panel intake (side)
2x 120mm fan intake (bottom, front I assume)
1x 120mm fan exhaust (rear)
PSU = exhausting
GPU = exhausting

I'd think the above is overkill, but maybe you're doing some crazy stuff or you live in a sauna. I'd probably start with just the two 230mm (OMG those are huge) and let the CPU, PSU, GPU fans do the rest.

 

[jesterb84]

devione: I would agree with 43st on the fan configuration. Your current directions are very strange and opposite of what is generally recommended. First error is at the top fans where you are pushing heat downwards when heat generally rises upwards. Furthermore, having the bottom fans exhausting is bad due to the close proximity to the floor (desktop, etc.) where that hot air is just going to:

1. Hit a flat surface and bounce back up
2. Due to heat rising naturally, will travel up into the case again.

Seriously, just think of a hot air balloon. The balloon rises in altitude as the air is heated - hence heat traveling upwards.

Take a look at the diagram I linked to above yours for reference. It's basically what 43st is describing...

 

[devione]

Thanks alot guys. I'll rearrange it.