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Help cool an overheating high end system

Last response: in Systems
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March 23, 2012 3:12:48 AM

OK, here's the deal. I built a $3,000 system for work in a physics lab. I received all of the parts exactly 1 month ago. The primary task is image analysis using Nvidia CUDA cores, but also general number crunching with the CPU. Of course, I do general web use, coding, plotting, etc.

The CPU is water-cooled while the rest uses airflow. The CPU has good temps (28-36 C) while the GPUs are generally cooking. When they're working they are at 75 C. It's bad news, so I need help. The same cards in a different case with more airflow are very cold to the touch, even when running under heavy load.

The parts are as follow:

CASE: Corsair Obsidian 800D
CPU: Intel i7-3930k, LGA 2011, 6-core 3.2 GHz.
RAM: 16 GB Corsair Vengeance Quad Channel, 1866 MHz
BOARD: Asus P9x79 Pro
COOLING: Corsair Hydro H100
GRAPHICS: Dual MSI N285GTX Superpipe OC GeForce GTX 285 (they were free)
POWER: PC Power and Cooling Turbo-Cool 1200W
STORAGE: Corsair 256 GB SSD and 1.5 TB Seagate Black Caviar 7200 rpm.


My question is simply how to produce sufficient airflow to cool this system. I have the H100's radiator mounted to the top of the case, filling 2 of the 3 grills. The third is left empty. I'm using the stock included fans that came with the case otherwise. I've noticed that they run particularly slowly, at about 760 rpm.

What do you guys suggest that I do? Is there a way to push air across the GPUs?

People are saying that this system is so great, so I assume I'm doing something wrong. Those GPUs shouldn't be so hot!

Any help would be appreciated. Thanks.
March 23, 2012 3:30:43 AM

75C isn't terrible for those cards - GPUs today still run in the 60-70C degree range even though they're more efficient.

Just make sure your case airflow is efficiently set up - front fans pulling air to the back, and your vertical fans exhausting upward. You could also add fans on the side panel to help move the air into/out of the card (whichever way the fans are blowing).

If that doesn't fix it, better fans are always an option as well, but they won't do any good until you have a good airflow setup.
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March 23, 2012 3:34:17 AM

Usually air coming from outside the PC case is cooler than the air coming out of the PC case. I suggest you buy two more fans and make it 4 fans pushing and pulling the air towards the inside of the PC case. If you you want to adjust the speed of the fans, I recommend you buying a fan controller. Here is a link for you to look if you are interested on my suggestion:http://www.newegg.com/Product/ProductList.aspx?Submit=E...
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March 23, 2012 3:46:24 AM

OK. I'm going to try the push-pull setup. I'm also going to fit a 3rd fan as an intake at the top of the case, next to the H100. I am going to replace the outlet fan on the back with something more powerful too. What are your thoughts about the fans on the bottom? What do I do there? Is there a way to blow air directly across the GPUs?
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March 23, 2012 4:00:05 AM

Where is the push-pull setup going? It may help the CPU temps, but it'll have no effect on the GPUs unless you can get that air near there.

Which way are the fans on the bottom pointing? Again, efficient airflow is the key (i.e. have everything going the same direction) - my Raven RV02 was able to cool anything because it was efficient even though the fans were only 1000RPM.

What's your noise requirement/desires? You can get some decently strong fans from Xigmatek, Cougar, and Cooler Master that'll push ~60 CFM at about 20dBA (about whisper quiet), but obviously you can get 100+ CFM fans but at much higher noise levels.
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March 23, 2012 4:02:11 AM

You work in a lab?
No access to Ln2 or liquid O2?
Cause that would cool everything juuust fine :-)
As mentioned 70'c is no issue, but had you considered a proper water loop with Cpu and cards on?
I'm thinking a big external radbox could be situated close enough if you are geek enough to build one :-)
Moto
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March 23, 2012 1:35:32 PM

boiler1990 said:
Where is the push-pull setup going? It may help the CPU temps, but it'll have no effect on the GPUs unless you can get that air near there.

Which way are the fans on the bottom pointing? Again, efficient airflow is the key (i.e. have everything going the same direction) - my Raven RV02 was able to cool anything because it was efficient even though the fans were only 1000RPM.

What's your noise requirement/desires? You can get some decently strong fans from Xigmatek, Cougar, and Cooler Master that'll push ~60 CFM at about 20dBA (about whisper quiet), but obviously you can get 100+ CFM fans but at much higher noise levels.




Yes, I just realized that last night that I don't need extra CPU cooling. The problem really is the GPUs. There's one stock fan at the bottom that I think pulls air in, but I'm not certain. Noise isn't a huge concern. So you think I should try out some new higher power fans and install them on the bottom vents?
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March 23, 2012 1:39:59 PM

I just can't imagine spending $3k on a good work PC and not getting new GPUs, especially if you need CUDA ;) 
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March 23, 2012 1:43:02 PM

boiler1990 said:
I just can't imagine spending $3k on a good work PC and not getting new GPUs, especially if you need CUDA ;) 


Well, I had two of these sitting around the office. I'm using them for now. They're fast enough for what I'm doing.

So do you think stacking two fans on the bottom will produce enough airflow?
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March 23, 2012 2:17:00 PM

I'm not sure how your airflow is setup right now (never owned/seen an 800D in person). I would much appreciate a sort of drawing showing fan locations and airflow.

I don't think stacking fans will work entirely too well, since CFMs aren't necessarily additive. You could replace the fans with some 120x38mm (vs standard 120x25) like the Scythe Ultra Kaze or Deltas, but they tend to get noisy.
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Best solution

March 23, 2012 3:52:06 PM

ASUS has an onboard fan controller that you need to set to "turbo." You need to fool around with that program so you can use your machine more efficiently.

Your problem is the 800D however. There are no openings on the front. It is designed to cool from the bottom. You need to make sure that the airflow coming in from the bottom is as unobstructed as possible. Make sure that the case has enough room to draw air in and let it out. Also do a temperature comparison with the case open. See what happens.

Make sure those screens are clean. You also need to take out everything that can be blocking airflow. Corsair likes to add extra cool stuff like bays for storage that some people don't use. Take those out if you are not using them. I don't know if you can with that case. Make sure that fan at the bottom of the main compatment is blowing as hard as it little blades can go.

Also, When you ad the fan on top next to the radiator, make sure that it is blowing out.

PS. Double check that the rear fan is actually blowing out. I've missed that one before.

Good luck!
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March 30, 2012 7:33:23 PM

voodooking said:
ASUS has an onboard fan controller that you need to set to "turbo." You need to fool around with that program so you can use your machine more efficiently.

Your problem is the 800D however. There are no openings on the front. It is designed to cool from the bottom. You need to make sure that the airflow coming in from the bottom is as unobstructed as possible. Make sure that the case has enough room to draw air in and let it out. Also do a temperature comparison with the case open. See what happens.

Make sure those screens are clean. You also need to take out everything that can be blocking airflow. Corsair likes to add extra cool stuff like bays for storage that some people don't use. Take those out if you are not using them. I don't know if you can with that case. Make sure that fan at the bottom of the main compatment is blowing as hard as it little blades can go.

Also, When you ad the fan on top next to the radiator, make sure that it is blowing out.

PS. Double check that the rear fan is actually blowing out. I've missed that one before.

Good luck!


Thanks a lot for all of the information. I'll be getting together some more powerful fans and following your advice. Thanks again.
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April 13, 2012 2:35:24 PM

voodooking said:
ASUS has an onboard fan controller that you need to set to "turbo." You need to fool around with that program so you can use your machine more efficiently.

Your problem is the 800D however. There are no openings on the front. It is designed to cool from the bottom. You need to make sure that the airflow coming in from the bottom is as unobstructed as possible. Make sure that the case has enough room to draw air in and let it out. Also do a temperature comparison with the case open. See what happens.

Make sure those screens are clean. You also need to take out everything that can be blocking airflow. Corsair likes to add extra cool stuff like bays for storage that some people don't use. Take those out if you are not using them. I don't know if you can with that case. Make sure that fan at the bottom of the main compatment is blowing as hard as it little blades can go.

Also, When you ad the fan on top next to the radiator, make sure that it is blowing out.

PS. Double check that the rear fan is actually blowing out. I've missed that one before.

Good luck!


Voodoo, are you sure that I should have that 3rd top fan blowing out? I just got a Noctua on there. Great fan so far. I have the 2 stock corsairs on top, along with the Noctua, and then the radiator is attached to the bottom of the corsairs. All 3 fans are blowing in. I'm waiting for the arrival of two 14cm fans, which will replace the bottom fan and the fan on the rear. The only fan blowing air out will be the fan on the rear.

Things have improved with the Noctua, but I do wish I had a way of blasting air across the GPUs. It seems like this case really wants you to water cool 2 or 3 GPUs!
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April 13, 2012 2:35:35 PM

Best answer selected by kedmond.
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