DIMM 3,4 proximity sensor indicating high temperature

Question

Mac Pro 2013

The 2013 revamp of the desktop Mac series known as the Mac Pro.

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Hugh @esencia

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crwdns2931729:0crwdne2931729:0: Ndz 3, 2018

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DIMM 3,4 proximity sensor indicating high temperature

hi,

I’ve been having high fan’s rpm for a long time.

After installing Macs Fan Control 1.4.11 I’ve realised that the DIMM 3,4 Proximity sensor is showing more than 85º C or more always. Even after a new boot upt.

I have 4x16gb RAM modules installed, but even with jus 2x modules in DIMM 1,2 it is still showing DIMM 3,4 proximity temperature really high.

What is or where is that sensor?

BTW. I tried to reset the SMC, but I’m not sure if I got it (I don’t know how to check if I had success with the reset). The steps I followed where:

Turn off

Unplug it for 15 seconds

Power it again

Turn it on after 5 seconds.

I’ve opened the Mac Pro and I’ve clean everything , even I replaced the thermal paste. Everything is less noisy, but that sensor has high temperature and I think is responsible for this issue.

Is it possible to know what are the threshold values of every sensor that the Mac is using for activating the fans?

A friend of mine who own the same machine seems to have higher threshold than mine because I can see lower rpm with much more CPU temperature.

Thanks

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Install this app: TG Pro take a snapshot of the main screen (make sure you get all of the sensors) and paste it here for us to see Adding images to an existing question

crwdns2934271:0Ndz 7, 2018crwdnd2934271:0 Dan crwdne2934271:0

thanks for your answer.

I've updated my question with the screenshot you told me.

crwdns2934271:0Ndz 9, 2018crwdnd2934271:0 Hugh crwdne2934271:0

Now carefully swap the memory modules around so the pair in slots 1 & 2 are swapped over with 3 & 4. Did the sensor for 1& 2 jump to the higher temp or did it stay with 3 & 4?

crwdns2934271:0Ndz 9, 2018crwdnd2934271:0 Dan crwdne2934271:0

It stays with the high temperature with 3&4 even after swapping the dimm modules. Even more, if I just put two dimm modules on 1&2 it is still saying that high temperature on 3&4.

If I reduced that temperature and assign a lower threshold based on cpu or vcpu, dimm 3&4 sensor can reach 95 degrees

crwdns2934271:0Ndz 9, 2018crwdnd2934271:0 Hugh crwdne2934271:0

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Install this app: TG Pro take a snapshot of the main screen (make sure you get all of the sensors) and paste it here for us to see Adding images to an existing question — Dan
thanks for your answer.

I've updated my question with the screenshot you told me. — Hugh
Now carefully swap the memory modules around so the pair in slots 1 & 2 are swapped over with 3 & 4. Did the sensor for 1& 2 jump to the higher temp or did it stay with 3 & 4? — Dan
It stays with the high temperature with 3&4 even after swapping the dimm modules. Even more, if I just put two dimm modules on 1&2 it is still saying that high temperature on 3&4.

If I reduced that temperature and assign a lower threshold based on cpu or vcpu, dimm 3&4 sensor can reach 95 degrees — Hugh

score 2 · Answer 1 · 2018-09-10T09:49:28-07:00

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Dan @danj

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crwdns2931729:0crwdne2931729:0: Ndz 10, 2018

crwdns2933897:0crwdne2933897:0

OK, This is not going to be easy ;-[

The CPU riser board has a problem. I’m not sure if the sensor its self is the issue or you have a power feed connector failure which is overheating.

If you look at these two images you’ll see there is not obvious sensor around the slots (either side). I would have expected there would have been something more visible. What I do see is the power feed stand offs are near the 3 & 4 memory slots. So any corrosion or even a loose connection could cause the connection point to heat up thus the sensor of that side is going off.

Follow this IFIXIT guide to get the fan unit off Mac Pro Late 2013 Logic Board Replacement following through to Step8 then pick up from Step19 and 20 to check the power feed connections to the CPU riser board.

If cleaning the connections & screws using 85% isopropyl alcohol (and you may need a pink pencil eraser if you’ve got corrosion) doesn’t solve the issue, then you’ll need to take the CPU riser board fully out to inspect it. You might even need to replace it.

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crwdns2944067:02crwdne2944067:0:

wow! thank you for your time and research!!!!

I was cleaning dust and the boards using isopropyl one week ago. But I didn't check inside the power unit itsel. Maybe the issue is inside. I'll try this again ASAP.

But where are the sensors? how could I find them?

How could I know if it´s a faulty measurement or a real high temperature?

crwdns2934271:0Ndz 13, 2018crwdnd2934271:0 Hugh crwdne2934271:0

What was the quality of the isopropyl you used? It could be the issue! You may need to reclean the board with a better grade (reagent 85% or better)

The only way is to use a non-contact thermometer to measure things. But I'm sure you've proven the issue as moving the module pairs from one set of connectors proves the issue is not the RAM its self but something unique within the area of slots 3 & 4 on the riser board. Thats were the power feed is also located which is why I would focus on it.

crwdns2934271:0Ndz 13, 2018crwdnd2934271:0 Dan crwdne2934271:0

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Mac Pro 2013

DIMM 3,4 proximity sensor indicating high temperature

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