Poor cooling with Megahalems rev B

darkip

darkip

darkip

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Joined
22 Dec 2008
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22
Location
London
Hi, I've just finished building my new rig and have been trying to overclock it to 4.0Ghz (with HT enabled) but am having some trouble with high temperatures.

The main components of the machine are:
i7 970 (Rev B1, not sure if that makes much difference)
Asus Rampage III Extreme
12GB Corsair XMS3 DDR3-1600 ram
Megahalems rev.b cooler with a Coolermaster Excalibur for push and Fractal Design Silent series for pull

I'm currently running at
Vcore 1.3V
QPI/DRAM (or Vtt as some people know it) 1.28

I'm testing stability using OCCT's linpack stress test and am seeing temperatures in Real Temp / Core Temp as high as 92C on two of the cores.

The question I'm really asking is whether this is reasonable performance from the Megahalems? I've already tried reseating the cooler + reapplying the thermal paste (Arctic MX-3) using the different techniques (rice sized blob and thin vertical line) but this hasn't made any difference.

Thanks in advance!
 
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Do you have any other fans to try? I don't know about the Coolermaster, but I'm sure the Fractal doesn't push much air.
 
The Coolermaster is a 2000rpm fan and certainly pushes a lot more air than the Fractal (a 1000rpm?). Unfortunately I don't have any more fans to hand :(

Ambient temperature in the room must be around 20C and this is the layout of the case:
 
Ideally, in a push/pull configuration you want to use two identical fans, the 1000 rpm fractal may be struggling to remove the hot air being pushed by a 2000 rpm fan.
 
Have you tried just having the coolermaster fan on its own? The slower fan could cause an issue but im not sure.

If not then its either you havnt reseated the heatsink properly or you need a better cooler. Have you checked whether the voltages are correct in the bios? More voltage = more heat.

Air flow in case? I dont see any intake fans only 1 exhaust, which would cause a negative air flow and by having 2 nvidia cards in there the hot air being outputted by the cards will raise the temperatures of the cpu. Try testing the temperature by having the side panel off.
 
I tried with the coolermaster fan on it's own as a pull fan and the difference was negligible. I'm using Load line calibration and I've checked the actual voltages using the motherboard utilities and cpu-z. My query is to whether these are temperatures I should expect with these voltages and this cooler?

There's 1 intake fan at the front of the case and the exhaust fan (another 1000rpm Fractal) you can see in addition to the PSU fan intake/exhaust.
 
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The mis-matched fans are the most likely culprit. Also, I'd debate the need for that rear exhaust fan. If you have two identical high CFM fans as a push/pull on that heatsink there will be more than enough airflow to act as your exhaust. As Matt said, make sure you have a decent air intake.

Another problem which you probably won't be able to do much is space in that case. It is rather cramped and bear in mind when you see benchmarks they are literally that - the majority of tests are conducted on an open bench because reviewers want to be able to chop and change hardware. This means so called 'lab tests' are conducted in situations that rarely reflect end user scenarios. When you consider the limited space in the case, combined with a high heat CPU and two GPUs, airflow needs to be as high and fast as possible.
 
Orcvader said:
Jiggle the heatsink and see if it's loose. It looks underpressured inside, try add some more intake fans?
Click to expand...
Heat sink isn't loose, the screws bolting it down are tight as they go.

Theophany said:
The mis-matched fans are the most likely culprit. Also, I'd debate the need for that rear exhaust fan. If you have two identical high CFM fans as a push/pull on that heatsink there will be more than enough airflow to act as your exhaust. As Matt said, make sure you have a decent air intake.
Click to expand...
Well, I'll try getting another Coolermaster 2000RPM and I'll remove that exhaust fan and place it at the front of the case to increase intake
 
darkip said:
Well, I'll try getting another Coolermaster 2000RPM and I'll remove that exhaust fan and place it at the front of the case to increase intake
Click to expand...

It's worth a try, computer chassis airflow isn't an exact science and there are far too many variables to give any guaranteed fixes, though there are some general rules that apply across the board.

My case is rather small itself and after hours of playing with different airflow configurations I found a simple intake and exhaust across the case worked best for me.
 
I have the option of putting the fans in the front of the case (although, the airflow is obstructed by the door) or I can put one in the top of the case? What do you reckon would be better?
 
I personally wouldn't intake on the top as heat rises and you'd be obstructing the natural flow of air, though that being said it could well work given the closeness of the chassis roof to your CPU cooler and may well do the trick.

I've never found my HDD's assembly temperatures rising above 30'c, even under the most stress I would ever put on them outside a torture test, whilst they may obstruct airflow of a low CFM fan, they wouldn't have a tremendous effect upon the temperature of the air supplied. Given that an Intel CPU has a fairly high running temperature anyway, it shouldn't present too much of a problem temperature-wise.

Having seen your case though, it would appear that a top-mounted intake may well work best. A great deal of GPU heat will end up being expelled by the obstructive CPU cooler anyway. Let me know what you find! :)
 
An update!

I replaced the slower pull and exhaust fans with Cooler Master Excaliburs and used the slower fans for intake at the front and side of the case and now I see a max core temperature of 80C under OCCT : LINPACK!

I also tried to tidy the cables a little:
 
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