Fan question.

Enclosures, modding, blowholes, and the power needed to run it all.

Moderators: Nemesis, SpotTheCat

Fan question.

Postposted on Sun Dec 28, 2008 9:41 pm

OK, I know its best to put your intake fans lower and your outtake fans higher in the case. I mean heat rises so.. What I need to know is it better to "push" or "pull" the air throught the case? btw I have a CM690 case if that matters. I'm getting ready to get some Skythe S-flex fans for it from Newegg.
crimsonjax
Gerbil
 
Posts: 54
Joined: Mon Dec 24, 2007 8:40 pm

Re: Fan question.

Postposted on Sun Dec 28, 2008 10:57 pm

Ahh yes, the age old question. There are good reasons for both camps. I prefer to run exhaust only because it puts the fans farther under my desk, making them quieter. It also exposes as much of the front filters in my P180 as possible.
SpotTheCat
Gerbilus Supremus
 
Posts: 12260
Joined: Tue Jan 28, 2003 11:47 pm
Location: a regular hole

Re: Fan question.

Postposted on Sun Dec 28, 2008 11:50 pm

The advantage of running intake is that less dust gets sucked in through your DVD drive, potentially prolonging its life.
(this space intentionally left blank)
just brew it!
Administrator
Gold subscriber
 
 
Posts: 36900
Joined: Tue Aug 20, 2002 9:51 pm
Location: Somewhere, having a beer

Re: Fan question.

Postposted on Mon Dec 29, 2008 9:11 am

just brew it! wrote:The advantage of running intake is that less dust gets sucked in through your DVD drive, potentially prolonging its life.

An advantage :D. It's really just a game on your preference.
SpotTheCat
Gerbilus Supremus
 
Posts: 12260
Joined: Tue Jan 28, 2003 11:47 pm
Location: a regular hole

Re: Fan question.

Postposted on Mon Dec 29, 2008 9:28 am

I prefer to have my fans push air rather than pull. It does control dust, especially if you use a filter. My setup right now has a 120mm filtered push, a 120mm pull, and the 80mm pull in the PSU. All the fans are very quiet.
flip-mode
Gerbil Khan
Silver subscriber
 
 
Posts: 9068
Joined: Thu May 08, 2003 11:42 am
Location: Cincinnati, OH

Re: Fan question.

Postposted on Mon Dec 29, 2008 11:14 am

The case has potential for 7, 12 cm fans. I assume this is over-kill to use all 7. :) How would some of you place your fans in the case? Found a drawing that shows fan locals for this case. Thanks!

Image
crimsonjax
Gerbil
 
Posts: 54
Joined: Mon Dec 24, 2007 8:40 pm

Re: Fan question.

Postposted on Mon Dec 29, 2008 11:32 am

It depends on the system. If it were one of my low power, quiet oriented systems I would put one exhaust fan on the rear facing the wall, I would seal up the top fans and the side panel, and put a filter (with no fan) on the front.

If that didn't keep things cool enough, I would put a very slow front fan in to keep the HDD alive, a top exhaust fan as exhaust (the one in the more rear), and open up the side panel holes with filters to balance the pressure.

The trick to using an exhaust-only setup is the inlets. You need to seal off everything but filtered front intakes. If you left the other ones open or filtered, you would risk losing your HDD to heat.
SpotTheCat
Gerbilus Supremus
 
Posts: 12260
Joined: Tue Jan 28, 2003 11:47 pm
Location: a regular hole

Re: Fan question.

Postposted on Mon Dec 29, 2008 2:21 pm

I would think that forced air would mix up the air in the case more and leave less change of a hot air pocket forming.

Sealing off the cracks in the case would seem to contribute to hot air pockets.

7 fans is toooo much.

1 front fan, 1 rear fan, 1 PSU fan

*or*

1 front fan and 1 PSU fan

If you are overclocking like crazy then all recommendations are off as it can get pretty particular.
flip-mode
Gerbil Khan
Silver subscriber
 
 
Posts: 9068
Joined: Thu May 08, 2003 11:42 am
Location: Cincinnati, OH

Re: Fan question.

Postposted on Mon Dec 29, 2008 4:39 pm

Image

How's that? I'll use the 7v trick on all intake fans to make around 18 CFM at ~700 RPM with the skythe s-flex E's. I'll use the same fans for the exhaust, but let them run at full 12v so they wil pull at 34 CFM at ~1230 RPM. The reason for the one fan on the side is that I would like to just have a passive cooler on the CPU, haven't decided though.

I'll have filters on all intakes and extra fan openings. I plan of using some sound pads on the interior to help seal up gaps and holes. Thoughts?
crimsonjax
Gerbil
 
Posts: 54
Joined: Mon Dec 24, 2007 8:40 pm

Re: Fan question.

Postposted on Mon Dec 29, 2008 4:45 pm

I've found over time that the sound of my S-Flex F models is pretty close to white noise, meaning that you can run them faster for better cooling without picking up objectionable noise. I've got 6 of them in a P182 turning around 900 RPM and I can still easily pick out drive seek chatter.
There are people that embrace the Oxford comma and people who don't. Never get between these people when drink has been taken. I use the Oxford comma and always will. The rest can sod off.
Captain Ned
Global Moderator
Gold subscriber
 
 
Posts: 19753
Joined: Wed Jan 16, 2002 6:00 pm
Location: Vermont, USA

Re: Fan question.

Postposted on Mon Dec 29, 2008 5:14 pm

Positive air-pressure in a case is absolutely better than negative. You'll get rid of ALL dust (with proper filters on the intakes) and less noise as fans transmit noise in the same direction as they're blowing.
I'd set most fans, front and side to intake with only the PSU and maybe one at the back, out (depending on GPU-fan). This will not only eliminate dust intake and reduce noise but also improve the circulation in the case as showed recently by Silverstone: http://www.youtube.com/watch?v=Qe-2ZqmS ... re=related

Also, too low an air-pressure in the case won't leave enough air to be sucked through the PSU, causing over heating there.

A negative pressure can never create less hot-spots tan positive as they work in the same way, only in reverse. Simple physics though will proove thata positive pressure will leave more air (and heat) to be moved by exhaust fans, thus creating better cooling. It's also possible that a lesser air pressure will conduct heat less efficiently as well as there are less particles to absorb the heat within the chassis but with the relative pressures involved we're talking theory here!
Pentium E2140 | Asus P5E-VM (G35) | 2GB HyperX 1066MHz (@800/3-4-4-12) | WD Blue 640GB (AAKS) | WD Green 1TB(EADS) | Samsung 2443BW | ASUS UL30VT (C2D SU7300, GF210M, 4GBRAM, 500GBHDD, 13")
Imperor
Gerbil
 
Posts: 66
Joined: Sun Jan 07, 2007 7:49 pm
Location: Stockholm, Sweden

Re: Fan question.

Postposted on Mon Dec 29, 2008 6:11 pm

Man, after reading this, I may just get 1 under-volted fan for the front and a pair of nice Skythe slipstreams. One for the back, and one for the top..
crimsonjax
Gerbil
 
Posts: 54
Joined: Mon Dec 24, 2007 8:40 pm

Re: Fan question.

Postposted on Mon Dec 29, 2008 6:46 pm

The only devices cooled by the case fans are the HDDs. The case fans do not cool the CPU or the GPU. The case fans provide bulk room-temperature air to the inside of the case and remove heated air from the case.

All the cooling for the CPU and GPU is done by the GPU and CPU heatsink/fans. These fans grab whatever air is closest to them and throw it against their heatsinks at high speed. This air removes heat from the heatsink and this is what cools the CPU and GPU. The case fans are only there to supply the ambient air and remove the heated air.

The message here is that if the air inside of your case is just a few degrees above ambient room temperature and your CPU and GPU are still running too hot, you don't need more case fans. You need better CPU/GPU heatsink/fans. On the other hand, if your CPU/GPU (at load) are within 5-10 degrees C of the inside-case air and your case air is many degrees above ambient, then you need more case fans.

I restate all this obvious stuff because I see people getting all wrapped up in positive/negative air pressures, which just misses the point. The fans for these machines are designed for both inlet and exhaust, which means that they're most efficient when they're operating at close to neutral pressures (not trying to pressurize a volume or to pull a vacuum). So just balance the inputs and outputs so that you get maximum appropriate airflow through the case and you'll get the best cooling possible.

And use filters. Pantyhose work great.
This problem was caused by Windows, which was created by Microsoft Corporation.
sluggo
Gerbil Jedi
 
Posts: 1531
Joined: Wed Feb 16, 2005 7:44 pm
Location: under the table and dreaming

Re: Fan question.

Postposted on Mon Dec 29, 2008 7:05 pm

Imperor wrote:Positive air-pressure in a case is absolutely better than negative. You'll get rid of ALL dust (with proper filters on the intakes) and less noise as fans transmit noise in the same direction as they're blowing.
I'd set most fans, front and side to intake with only the PSU and maybe one at the back, out (depending on GPU-fan). This will not only eliminate dust intake and reduce noise but also improve the circulation in the case as showed recently by Silverstone: http://www.youtube.com/watch?v=Qe-2ZqmS ... re=related

Also, too low an air-pressure in the case won't leave enough air to be sucked through the PSU, causing over heating there.

A negative pressure can never create less hot-spots tan positive as they work in the same way, only in reverse. Simple physics though will proove thata positive pressure will leave more air (and heat) to be moved by exhaust fans, thus creating better cooling. It's also possible that a lesser air pressure will conduct heat less efficiently as well as there are less particles to absorb the heat within the chassis but with the relative pressures involved we're talking theory here!

It's not absolutely better! I run negative pressure so I can get away with fewer fans and better filtering. The P180 is well sealed, and the front filters work wonderfully even without fans in them.
SpotTheCat
Gerbilus Supremus
 
Posts: 12260
Joined: Tue Jan 28, 2003 11:47 pm
Location: a regular hole

Re: Fan question.

Postposted on Mon Dec 29, 2008 8:05 pm

Imperor wrote:Positive air-pressure in a case is absolutely better than negative. You'll get rid of ALL dust (with proper filters on the intakes) and less noise as fans transmit noise in the same direction as they're blowing.

Yes, but... the front of the case is typically closer to the user, so the noise issue is probably a wash.
(this space intentionally left blank)
just brew it!
Administrator
Gold subscriber
 
 
Posts: 36900
Joined: Tue Aug 20, 2002 9:51 pm
Location: Somewhere, having a beer

Re: Fan question.

Postposted on Tue Dec 30, 2008 11:10 am

Captain Ned wrote:I've found over time that the sound of my S-Flex F models is pretty close to white noise, meaning that you can run them faster for better cooling without picking up objectionable noise. I've got 6 of them in a P182 turning around 900 RPM and I can still easily pick out drive seek chatter.


I assume your using a fan controller? Mind if I ask what kind? Thanks.
crimsonjax
Gerbil
 
Posts: 54
Joined: Mon Dec 24, 2007 8:40 pm

Re: Fan question.

Postposted on Sat Jan 03, 2009 5:22 pm

Found some pretty sweet info on the matter: http://icrontic.com/articles/pc_airflow ... ling_guide
Pentium E2140 | Asus P5E-VM (G35) | 2GB HyperX 1066MHz (@800/3-4-4-12) | WD Blue 640GB (AAKS) | WD Green 1TB(EADS) | Samsung 2443BW | ASUS UL30VT (C2D SU7300, GF210M, 4GBRAM, 500GBHDD, 13")
Imperor
Gerbil
 
Posts: 66
Joined: Sun Jan 07, 2007 7:49 pm
Location: Stockholm, Sweden

Re: Fan question.

Postposted on Sat Jan 03, 2009 6:41 pm

Imperor wrote:Found some pretty sweet info on the matter: http://icrontic.com/articles/pc_airflow ... ling_guide

That pretty much sums up my experience. I prefer to just use the rear fan. On a P182, I sometimes put a lower/middle fan in to help with the HDDs.
SpotTheCat
Gerbilus Supremus
 
Posts: 12260
Joined: Tue Jan 28, 2003 11:47 pm
Location: a regular hole

Re: Fan question.

Postposted on Sun Jan 04, 2009 10:56 am

OK, been reading some things here and at silientpcreview.com and I think this tis the set up I'll start with..
Image

I'll run the front fan at 7v to cut down of noise. Thoughts?
crimsonjax
Gerbil
 
Posts: 54
Joined: Mon Dec 24, 2007 8:40 pm

Re: Fan question.

Postposted on Sun Jan 04, 2009 12:08 pm

crimsonjax wrote:
Captain Ned wrote:I've found over time that the sound of my S-Flex F models is pretty close to white noise, meaning that you can run them faster for better cooling without picking up objectionable noise. I've got 6 of them in a P182 turning around 900 RPM and I can still easily pick out drive seek chatter.
I assume your using a fan controller? Mind if I ask what kind? Thanks.

I'm using the fan headers on my Abit IP35-Pro. Between the BIOS and the uGuru software I can set individual temperature/speed profiles for the CPU fan and the 5 chassis fans using 1 of 3 temp sources, the CPU, the PWM circuits, or the internal case temp.
There are people that embrace the Oxford comma and people who don't. Never get between these people when drink has been taken. I use the Oxford comma and always will. The rest can sod off.
Captain Ned
Global Moderator
Gold subscriber
 
 
Posts: 19753
Joined: Wed Jan 16, 2002 6:00 pm
Location: Vermont, USA

Re: Fan question.

Postposted on Sun Jan 04, 2009 12:17 pm

Captain Ned wrote:
crimsonjax wrote:
Captain Ned wrote:I've found over time that the sound of my S-Flex F models is pretty close to white noise, meaning that you can run them faster for better cooling without picking up objectionable noise. I've got 6 of them in a P182 turning around 900 RPM and I can still easily pick out drive seek chatter.
I assume your using a fan controller? Mind if I ask what kind? Thanks.

I'm using the fan headers on my Abit IP35-Pro. Between the BIOS and the uGuru software I can set individual temperature/speed profiles for the CPU fan and the 5 chassis fans using 1 of 3 temp sources, the CPU, the PWM circuits, or the internal case temp.

That is nice about the IP 35 pro , I use the it the same way.
Core I7 2600K @ 4.8 | Asrock P67 Extreme 4 | 16 gig Corsair | EVGA Superclocked GTX 570 | WD Black 1 TB HDD | Seasonic X-850 W

Phenom II 940 | Gigabyte MA78G-DS3HP | 2x2 gig G-Skill dr2 800 | 500 W Seasonic | WD 640 HDD | Sapphire 4890 1 gig
tsoulier
Minister of Gerbil Affairs
 
Posts: 2917
Joined: Mon Aug 09, 2004 5:17 am
Location: South Louisiana

Re: Fan question.

Postposted on Tue Jan 06, 2009 6:55 pm

Captain Ned wrote:I'm using the fan headers on my Abit IP35-Pro. Between the BIOS and the uGuru software I can set individual temperature/speed profiles for the CPU fan and the 5 chassis fans using 1 of 3 temp sources, the CPU, the PWM circuits, or the internal case temp.


Sweet, I'll keep that in mind when I'm getting a MB. Thanks.
crimsonjax
Gerbil
 
Posts: 54
Joined: Mon Dec 24, 2007 8:40 pm


Return to Cases and Power Supplies

Who is online

Users browsing this forum: No registered users and 1 guest