Poor cooling with Megahalems rev B?

[darkip]

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.

Ambient temperature in the room must be around 20C and this is the layout of the case:


Thanks in advance!

[Darkboss]

Do the temps lower when you have the side panel off the case? If so then there might be some airflow issues. How many fans do you have for intake and exhaust in the case?

Some cable management might be needed as well to help improve the airflow in the case. Is your psu drawing air from the inside of the case to the outside of the case? If so it might be robbing some air from reaching the top of the case if you have a lower intake fan . I thought mostly the fans on the psu need to bring cool air into the psu from the bottom of the case (if you have that option) and out the exhaust in the psu.

A silly question but when you stress test the cpu, how do the fans react to the cpu? Does the rpm lower or remain steady at their rated speeds? What are the speeds and cfm on the fans? I'm to lazy to search the internet. lol.

[halfwaythere]

One of the most common mistakes is using a slower fan for pulling. Remove it check the paste imprint on the heatsink base and maybe post some pictures here. You could have a cpu with a very uneven ihs or worst case scenario a very hot one.

[darkip]

Do the temps lower when you have the side panel off the case? If so then there might be some airflow issues. How many fans do you have for intake and exhaust in the case?

Yes, the temperatures seem to drop by a few degrees. I have 1 intake fan at the front of the case but it's somewhat blocked by the door, the one exhaust fan is visible in the back of the case in the photo.

Some cable management might be needed as well to help improve the airflow in the case. Is your psu drawing air from the inside of the case to the outside of the case? If so it might be robbing some air from reaching the top of the case if you have a lower intake fan . I thought mostly the fans on the psu need to bring cool air into the psu from the bottom of the case (if you have that option) and out the exhaust in the psu.

Yes, the PSU is currently mounted such that the intake fan is facing upwards so drawing air from inside the case. So you suggest turning it over? Would this not in fact increase the temperature in the case?

A silly question but when you stress test the cpu, how do the fans react to the cpu? Does the rpm lower or remain steady at their rated speeds

The rpm remains constant at the rated speed, Q-Fan or whatever it's called is disabled in the BIOS.

What are the speeds and cfm on the fans? I'm to lazy to search the internet. lol.

Push - Cooler Master Excalibur
Speed: 600 - 2000 RPM ± 10%
Air Flow: 26.4 - 85.6 CFM ± 10%

Pull - Fractal Design Silent Series 120mm
Speed 1000 RPM ± 10%
Air Flow: 38.3 CFM

The intake and exhause fans are also the Fractal Design Silent Series 120mm.

One of the most common mistakes is using a slower fan for pulling

I've got another 2 of the Coolermaster Excalibur coming tomorrow so I'll sort that out.

I'm thinking of moving the intake fan from the front of the case to the top given the door must be blocking most of the airflow?

[Sam_oslo]

That's too high for Megahalems, for sure.

Is that 2 x GTX 480 you having in here? In any case, that SLI can radiate a lot of heat in your case and be a part of your problem. You need a lot of airflow to cope with that, try with one of them and see what kind of temp you get. But your may have other problems too.

[darkip]

Is that 2 x GTX 480 you having in here? In any case, that SLI can radiate a lot of heat in your case and be a part of your problem. You need a lot of airflow to cope with that, try with one of them and see what kind of temp you get. But your may have other problems too.

It's 2 x GTX 470 (so effectively yes). I'm hitting these temperatures whilst stress testing the CPU so the GPUs are idle.

[Sam_oslo]

It's 2 x GTX 470 (so effectively yes). I'm hitting these temperatures whilst stress testing the CPU so the GPUs are idle.

I would put a fan right behind those and push the hot air backward, Otherwise your CPU will suck in that heat. You have to isolate that heat by other means too. You need a really good air flow for that setup anyways.

EDIT, after looking closer at your picture,
Can you move thee upper GPU down? That's too close to your CPU.
You PSU is mounted up-down too.

[darkip]

EDIT, after looking closer at your picture,
Can you move thee upper GPU down? That's too close to your CPU.
You PSU is mounted up-down too.

I can't really move the upper GPU as the pci express slots on the board share bandwidth between each two.

I'm aware of the PSU, but surely it's in fact helping things as it's taking some of the hot air away from the GPUs?

[Sam_oslo]

I can't really move the upper GPU as the pci express slots on the board share bandwidth between each two.

I'm aware of the PSU, but surely it's in fact helping things as it's taking some of the hot air away from the GPUs?

I see the problem with GPU, but that PSU won't do much good that way. Probably you need a better case, with 8 slots, then you can use PCIe 2 and 4 on RE3? I would definitely try to move that GPU down. You need at least 3-4 good intake fans + a fan right behind those GPU, too. Those GPUs would do much better with positive pressure, then they will dump the heat outside.

I think your biggest problem is the lack of air-flow inside your case. But you may have other problems too.

[joshd]

Sam_oslo, which of your 5650s has the megahalem on it? Also do you have linpack temps for them?

[gatecrasherlok]

You need to change the orientation of the fans you have in the setup right there on the cpu and rear exhaust. The push fan can go up to 2000 rpm yet your max pull fan is only rated at 1000rpm max. This will cerrtainly cause problems with the airflow. Try switching them the other way round with the excalibre pulling air and the fractal pushing. While your at it the rear exhaust fan should at least be equal or hgher rpm performance to your pulling fan.

[darkip]

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:

[Sam_oslo]

Sam_oslo, which of your 5650s has the megahalem on it? Also do you have linpack temps for them?

On CPU#2 which is generally cooler, but no linpack runs here. It keeps under 56'C (hottest core) under Prime-run. But this is a low-volt summer-setup with only 1.16v, and I'll see if it can keep up when I push it to winter-setup soon.

[stangracin3]

i'd bet it would be even cooler if you didnt have all your ram banks full.

as you have it now, you are hammering the memory controller

[sn0man]

i'd bet it would be even cooler if you didnt have all your ram banks full.

as you have it now, you are hammering the memory controller

Aside from the already cramped case, I'd agree with this. Running with 12GB and all DIMM slots filled is pretty stressful on the CPU - but there's also the heat being given off by the RAM itself, which gets hotter when all slots are used.

[darkip]

I understand the stress the additional RAM puts on the processor + the heat it adds but unfortunately I need it

[sn0man]

I understand the stress the additional RAM puts on the processor + the heat it adds but unfortunately I need it

Just giving some insight on a few things people may not know or immediately realize. If you make use of it, then it should stay - no need to feel bad.

[darkip]

Given the amount of memory I'm using and the voltages I'm using, are these reasonable temperatures from the megahalems?

Side-note: When CPU hits 100%, my rig sounds like it's about to take off :P

[sn0man]

Given the amount of memory I'm using and the voltages I'm using, are these reasonable temperatures from the megahalems?

Side-note: When CPU hits 100%, my rig sounds like it's about to take off :P

The improved temps of 80C? Sure, that's much more in the ballpark.

And fan noise is just something you have to deal with on air cooling.

[darkip]

The improved temps of 80C? Sure, that's much more in the ballpark.

80C is actually the temperature of the hottest core, the average temperature across the 6 cores is 75C

[sn0man]

80C is actually the temperature of the hottest core, the average temperature across the 6 cores is 75C

Sounds good to me.

[aythrea]

just a thought here. isn't there a fan on the underside of your PSU? Flipping it over so the fan grabs some of the exhaust air from the video cards could also add some dumping ability. You might consider finding some pci slot covers with grills cut into them to give the moving air another way out. Try to run as much of the unused cables behind your motherboard tray where you can, and bundle the rest with some velcro close to the PSU. Moving your SSD to the bottom slot also might help relieve some of the air obstruction.

I'm not sure if I missed it or it wasn't mention, but what case is that? You might have to create your own cable management holes in the mobo tray... if you feel industrial enough.

[vengance_01]

Also those 470's in SLI will really dump a ton of heat in your case.