High motherboard temperatures

[Raxxath]

I've been working on a liquid cooling build for a while now- recently I threw it together on air cooling to see what things would look like, and to find any problems. There were plenty, perhaps the most disturbing is how high the motherboard temperatures are. According to Asus PC Probe II, they are...

MB- 45C
NB-45C
SB-49C

...at idle. This is on an Asus Blitz Formula, no voltage changes or overclocks. On my previous board, a Bad Axe 2, the NB and MB temperatures rarely went over 43C, even during the summer. My cooling now is better, and its 60F or so in the house, yet I'm still getting these crappy temps. On a related note, does the MB temperature stand for the RAM temperature?

When I first start up the computer, all the temperatures are a good 10-15C lower, then climb up to these levels over a few minutes. My fans are all low speed Yate Loons at 7v(two intake, one exhaust), turning them up to 12v makes a 1C difference at most. Putting a big house fan blowing over the side makes the temperatures all plummet, which leads me to believe its an airflow problem. When I go to liquid cooling, I'm aiming for a silent build, so this has me worried, as I can't have loud fans everywhere. Also, I was under the impression that Lian Lis have good airflow- it looks like it should, at least better than my old Thermaltake Armor.

I'll include a picture to give you an idea of things. I'll appreciate any help.

 

[BillParrish]

do not see the two intakes where are they mounted ?

Never thought I would say this, I think your airflow is too good, that case is so unobstructed the air comes in and goes right out the back due to that nice 120mm and all the grilling. I do not think you have much air moving over the motherboard at all other than the exhaust from the stock cpu fan. When you watercool you are going to have temps sky high at the VMR MosFETS. You need some air (as proven by your house fan), hitting that motherboard "head on" from the side. The power supply in the bottom would also "steal" your cool intake air by creating a direct air stream/flow from lower front directly into the power supply and out the back. Ditto the video card.

Once you get your rad fans running (I am assuming there are on the top sucking air out of the case) it might help pull cool air towards the top and over the board. If they will be on the bottom of the rad and pulling cool air into the case and exhausting over the board that would probally help too, that a big rad so the air will not be all that hot and just a little air movment over whatever is hot on that mother board will help a lot.

I would play with flipping that read 120 around and making it an intake, setup your rad fans to blow or suck air out of the case and a 120 mm side panel fan aimed right at the cpu area. 7V would probally work, that side panel fan hitting the top half of the motherboard "head on" would probally fix your concern. A flap or air deflector so that rear fans airstream is aimed more towards the motherboard is another idea. Thin clear acrylic sheet as found in cheap picture frames is easily cut and a bath in boiling water and carefull bending allow you to make curved shapes.

 

[Raxxath]

do not see the two intakes where are they mounted ?

Never thought I would say this, I think your airflow is too good, that case is so unobstructed the air comes in and goes right out the back due to that nice 120mm and all the grilling. I do not think you have much air moving over the motherboard at all other than the exhaust from the stock cpu fan. When you watercool you are going to have temps sky high at the VMR MosFETS. You need some air (as proven by your house fan), hitting that motherboard "head on" from the side. The power supply in the bottom would also "steal" your cool intake air by creating a direct air stream/flow from lower front directly into the power supply and out the back. Ditto the video card.

Once you get your rad fans running (I am assuming there are on the top sucking air out of the case) it might help pull cool air towards the top and over the board. If they will be on the bottom of the rad and pulling cool air into the case and exhausting over the board that would probally help too, that a big rad so the air will not be all that hot and just a little air movment over whatever is hot on that mother board will help a lot.

I would play with flipping that read 120 around and making it an intake, setup your rad fans to blow or suck air out of the case and a 120 mm side panel fan aimed right at the cpu area. 7V would probally work, that side panel fan hitting the top half of the motherboard "head on" would probally fix your concern. A flap or air deflector so that rear fans airstream is aimed more towards the motherboard is another idea. Thin clear acrylic sheet as found in cheap picture frames is easily cut and a bath in boiling water and carefull bending allow you to make curved shapes.

Thanks for the reply, Bill. The two intakes are mounted vertically on the front bottom- can't quite see them from that angle. I think you could be right about the airflow missing the motherboard.

I originally planned on having the radiator sucking air out of the case, but now I'm reconsidering that. I think the cool air flowing down could really help the non-liquid cooled temperatures, but I'm not sure which fans I would have exhaust instead. I'm also worried about dust, as I don't have filters on the top, just fan grills, and my house is very dusty. I'd feel a little foolish exhausting from the front too because I do have filters there. If I kept it pulling air out of the case, I can see the hot air heating up the radiator too much.

I started out planning on having a single loop for just the CPU and GPU. Then I wanted to add the northbridge. Now I'm thinking of adding the mosfets and all... . My main goal here is silence, along with high performance while remaining as aesthetically pleasing as possible. That makes things like side fans very undesirable for me, unfortunately. My computers have always been loud and overheating all the time- I really want to get this one perfect. The best luck I've had so far was when my computer wasn't in a case at all, with just two Yates at 7v, and I haven't seen comparable temps since.

 

[Raxxath]

I just tried turning off the case fans all together. After a few minutes of no airflow, other than the CPU, GPU, and PSU, the CPU temperature went up 2C and the southbridge fluctuated between 49 and 50 a few times. No other changes. So its a case airflow design problem? The PC-A70B is so similar to the G70, which is a widely used and loved case, it seems very odd that it would have such a problem.

The only real possible, practical solution I'm seeing right now is flipping the radiator fans to push air downward, and that's going to open up a few more problems for me. I'll see if I can give it a try today...

 

[IRML]

either you have a small motherboard or that is one of the biggest cases I've ever seen!

 

[BillParrish]

aye that is a monster.

Raxxath, well fans can easily be flipped over and nothing like a rainy afternoon of airflow adjustments. I would not worry about it too awful much until you get the "real" system up and running and then you can tune. I found out my front fans were not doing anything much at all by using an insense stick to watch the air flow. Short session with tin snips and electric drill fixed that. So bottom line its all easily tweaked once you get it up and running.

Damn nice cable routing, really like that idea with the main motherboard cable, gonna steal that on my next personal build. If you can afford it the mosfet blocks are the bomb. As you may have noticed I am big on keeping those components around the cpu area cool for stability and long life.

hmm it just occured to me, ask Asus EXACTLY where that motherboard temp sensor is located. on Gigabytes it near the end of the PCI-e slot and so picks up a lot of heat from the backside of the video card because the power supply cirucity for the video card is out there on the end. Kinda makes for a false reading. So the location of that sensor might shed some light on if the issue is one to be very concerned about or one that is just to be considered as you finish up your plans.
Man the inside of that case is shiney.

Consider grills for the rad or rad fans regardless. Filters are a pain to clean constantly but I just spent an hour with a toothbush getting the crap out of my rads and having it fall all over my case. Too lazy to lug it to the garage and fire up the air compressor. Other fans, eh, not hard to clean, dust in the rad, major pain and major impact on cooling. It had been a year +, coretemp at idle dropped 3 C .

doh, just noticed your nice MB with the MCH cooling block as part of the heatpipe assembly. If that thing is tuned up, here is what concerns me, I think this is a different version of board but it sound like something to be carefully checked as it appears you are absolutely "going to do this one right". /salute.

http://www.anandtech.com/mb/showdoc.aspx?i=3149&p=2

Moving on, we find the elaborate ROG heatsink designs ASUS employs to cool the Northbridge, Southbridge, and PWM areas. For the Maximus Formula SE, ASUS has employed a hybrid design consisting of a water block that is spot epoxy glued to a large heatsink that connects the Southbridge and Northbridge together with a heatpipe. The heatpipe continues further, covering part of the separate PWM heatsink, with an Aluminum fin section. A small fan is supplied that clips onto the Aluminum section of the heatsink, helping to cool the Northbridge and we suggest using it.

ASUS supplies both 3/8" and 1/2" tubing adaptors together with spring clamps to hold tubing in place. Unfortunately, our high flow pumps (Petra Top DDC Ultras) were too much for the 1/2" spring clamps. Using the supplied 1/2" clamps, our tubing actually came loose and shot off the barbs. Bottom line: screw type hose clips are a safer bet for high-pressure water cooling pumps. Initial testing with the stock solution using our upper-end water-cooling solution showed little temperature gains over air-cooling using 2x120mm fans over the area. During testing our water block actually came loose, and we were a little surprised to find that there was little contact between the heatsink and NB water block. No thermal paste was used in the stock design to ensure contact between the spots of epoxy glue that had been used to bond the two surfaces together.

Because there was very little contact between the Northbridge water block and the heatsink, it's no wonder there were no initial gains from using water-cooling. We re-attached the block using a combination of thermal paste (in the center of the block) and epoxy (around the perimeter). We also checked the contact between the chipset IHS (Integrated Heat Spreader) and the Northbridge heatsink assembly. The footprint left by the pad showed around a 60% contact surface, with the center of the NB IHS making very little contact with the heatsink. We scraped away the flaky thermal pad and used thermal paste in its place. The increased surface contact of the two modifications lead to a ~9C drop in load temperatures and certainly helped in overall board stability when overclocking.

So another of my pet peeves is the heatpipe, I highly recommend removing it entirely and remounting with "real" hardware and good thermal paste. But well worth the effort as it will really pay off with that waterblock/heatpipe thingy. I might be misunderstanding and you intend to junk the whole pipe assy for indivisual blocks, better still.

 

[Raxxath]

Damn nice cable routing, really like that idea with the main motherboard cable, gonna steal that on my next personal build. If you can afford it the mosfet blocks are the bomb. As you may have noticed I am big on keeping those components around the cpu area cool for stability and long life.

hmm it just occured to me, ask Asus EXACTLY where that motherboard temp sensor is located. on Gigabytes it near the end of the PCI-e slot and so picks up a lot of heat from the backside of the video card because the power supply cirucity for the video card is out there on the end. Kinda makes for a false reading. So the location of that sensor might shed some light on if the issue is one to be very concerned about or one that is just to be considered as you finish up your plans.
Man the inside of that case is shiney.

Consider grills for the rad or rad fans regardless. Filters are a pain to clean constantly but I just spent an hour with a toothbush getting the crap out of my rads and having it fall all over my case. Too lazy to lug it to the garage and fire up the air compressor. Other fans, eh, not hard to clean, dust in the rad, major pain and major impact on cooling. It had been a year +, coretemp at idle dropped 3 C .

I got halfway through hiding all the cables, until the 8-pin CPU connector wouldn't reach from behind the motherboard tray, and kind of gave up after that, for now at least. I would not recommend doing what I did to hide the 24-pin connector, because its a lot of work and makes the removable motherboard tray useless. I would only recommend it if you are going for perfection in a windowed case, like I was .

As for the location of the sensor, its temperature lowers when I have a fan blowing on either the top or bottom half of the board, so I'm really not sure. I bet it could be right around the video card, as you said. I doubt I'd get much help from Asus, I've heard their customer support is terrible from a number of sources, but they make great boards.

The filters I had in the front of my old Thermaltake Armor weren't hard to clean, just took a vacuum every week or two. My main concern is how the filters on the top would look, and how much they might impede airflow.

doh, just noticed your nice MB with the MCH cooling block as part of the heatpipe assembly. If that thing is tuned up, here is what concerns me, I think this is a different version of board but it sound like something to be carefully checked as it appears you are absolutely "going to do this one right". /salute.

So another of my pet peeves is the heatpipe, I highly recommend removing it entirely and remounting with "real" hardware and good thermal paste. But well worth the effort as it will really pay off with that waterblock/heatpipe thingy. I might be misunderstanding and you intend to junk the whole pipe assy for indivisual blocks, better still.

I originally ruled out removing the heatpipe at all, because I didn't want to get that in-depth. This will be my first water-cooled PC, and only the second real rig I've ever built myself, so that would be quite daunting. I've seen pictures of removed Asus heatpipes that took the Northbridge with them. Apparently they use an epoxy on them that once hardened, is extremely difficult to remove properly. Seeing how things are now is making me consider liquid cooling everything, though.

either you have a small motherboard or that is one of the biggest cases I've ever seen!

Its an ATX motherboard, so yeah, its a pretty big case.

 

[Raxxath]

I flipped the fans on the top so that they're sucking air into the case. No change in temperatures. I used poster board to try to route air from the front intakes to the motherboard. No change in temperatures.

When this is water cooled, there might be some less heat, but there will be a lot less airflow because of no CPU fan. I'm having this much trouble at stock settings and idle, AND the winter. I can only imagine what it will be like benchmarking, overclocked, during the summer...

I'm sick of putting so much thought and effort into this project, only to get more and more odd problems and difficulties. I've seen so many people kinda throw things together and get great results. Now I'm looking at remounting the heatpipes. With my luck, I'll rip the Northbridge right off...

 

[Raxxath]

I hate to bump again, but does anyone have any suggestions? I'm really running out of ideas here.

It looks like my last chance is remounting the heatpipes, but that will void my warranty I'm sure, something I really don't want to do on a $300 motherboard.

 

[fantomau]

Forgive me if I am wrong, But we have the same PSU and mine is not upside down. The PSU's fan blows hot air out the bottom, Not upwards towards the other components.

I also have 4 intake fans in front (Wont dare remove those) and a Zalman 9500LED HS/F. But I realize your WCing, Not air.

I think for 1 thing is if you put the PSU the other way (With the words not upside down), Then check the temps, Maybe that might do some good. If the PSU blows hot air upwards, Wouldnt the case and other components be hotter than usual with hot air rising towards the top? and w/ NO intact fans from the front to blow the air rising from the PSU, The hot air would be linger around?

 

[Raxxath]

Forgive me if I am wrong, But we have the same PSU and mine is not upside down. The PSU's fan blows hot air out the bottom, Not upwards towards the other components.

I also have 4 intake fans in front (Wont dare remove those) and a Zalman 9500LED HS/F.

I think for 1 thing is if you put the PSU the other way (With the words not upside down), Then check the temps. If the PSU blows hot air upwards, Wouldnt the case be hotter than usual?

I was under the impression that the fan on this PSU was an intake, and that hot air was exhausted out the back. I'll try flipping it though, thanks for the suggestion.

 

[fantomau]

either you have a small motherboard or that is one of the biggest cases I've ever seen!

Its a BIG case for sure as I own it too, But its not bigger than the CoolerMaster Cosmos.

 

[fantomau]

I was under the impression that the fan on this PSU was an intake, and that hot air was exhausted out the back. I'll try flipping it though, thanks for the suggestion.

I'm not sure, I could be wrong, But its just that when I saw the PSU upside down, I thought that maybe that could be the cause. Its just that every case I've seen this PSU installed has been the other way. If I'm wrong, My apologies.

 

[Raxxath]

Well, I tried flipping it- no change in temperatures.

I did find that placing a 120mm fan even on very low speed facing the area on the motherboard between the CPU fan and sound card reduced the "Motherboard" sensor's temperatures by 10C. So it appears that's about where that sensor is located, and where hot air is pocketing, for some reason. I need to figure out what that reason is, or find a good way to cool it properly. Even though that fan was also blowing over the Northbridge, it did very little for its temperatures, so I'll probably end up remounting or replacing the heatpipes.

One thing I don't understand is why the Southbridge is so hot. It should be getting lots of direct, fresh air, no?