Computers & Electronics

CPU core temperature difference between motherboards?

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  • Jun 9th, 2021 3:37 pm
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CPU core temperature difference between motherboards?

Have a i7 8700 non k cpu that I put in a MSI B360 motherboard. According to both Hwinfo and HWmonitor, core 0 and core 1 are significantly hotter than the other cores, 15-20C hotter. Thought it was a bad mount with the 120mm AIO i was using, remounted multiple times, no change. Switched to a Noctua D14, temperature difference still present although overall temperature is lower since its a better cooler. Wouldnt matter as much if the temperature difference didn't make the CPU thermal throttle.

Changed motherboard to a Asrock Z370 I have from another build. Mounted the Noctua D14, suddenly the temperature between the cores are more consistent. Switched to the 120mm AIO, temperatures are great with the same CPU but ASrock board.

Any ideas? Could it be a bad temperatures sensor on the MSI motherboard? Thought the CPU temperature sensors are built in the CPU now right?

I've checked I was using all the correct mounting hardware for the AIO and air cooler. Just not sure what could be causing such a big discrepancy in core temp aside from poor mounting or motherboard issue.
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Intel is very secretive about the chipset-to-CPU interface so there is very little information available to help draw a firm conclusion on what might be happening here. It's possible there are issues with the CPU microcode in the MSI firmware causing the CPU to run hotter, or that the MSI CPU power supply is providing higher voltages to some parts of the chip than others. It might be possible that the MSI board is feeding higher clock frequencies to the hotter cores.

If the CPU was too hot overall, then the most likely explanation (once you've ruled out heatsink mounting issues, poor airflow, and other physical problems) would be that the fan speed control algorithm on the MSI board is not aggressive enough and doesn't ramp up the fans far enough to keep the CPU cool. This may be tweakable in the firmware (BIOS) setup.

The CPU temperature sensors are embedded in the CPU die(s). There will be several (possibly dozens or more) sensors per core, and the CPU will only report the sensor that measures the highest temperature.
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Some motherboard manufacturers 'cheat' by ignoring the Intel specs and essentially overpowering the CPU in order to make performance look better on their products.

Asrock tends to follow the Intel spec more closely, because their VRMs suck.
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A slight update. I switched my i7 8700K ( a different CPU then the suspect one ) into the MSI board coupled with the 120mm AIO. Does not experience temperature difference like the other CPU. Thermals are also more under control with only 5C difference between highest cores and lowest cores which is more " normal" . Temperature does not get much higher than mid 80s even after a 10 min Cinebench R23 run, which I think is expected from a 120mm AIO. With the problem CPU, 2/6 core will get to 100C and throttle.

I've mounted and remounted the Coolers so many times now testing various combinations. Maybe the MSI board just doesn't like the original i7 8700 non k?.... I am stumped. Besides getting a different motherboard, not sure what else I can test.
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Delid the problem CPU and repaste.
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coilz wrote: A slight update. I switched my i7 8700K ( a different CPU then the suspect one ) into the MSI board coupled with the 120mm AIO. Does not experience temperature difference like the other CPU. Thermals are also more under control with only 5C difference between highest cores and lowest cores which is more " normal" . Temperature does not get much higher than mid 80s even after a 10 min Cinebench R23 run, which I think is expected from a 120mm AIO. With the problem CPU, 2/6 core will get to 100C and throttle.

I've mounted and remounted the Coolers so many times now testing various combinations. Maybe the MSI board just doesn't like the original i7 8700 non k?.... I am stumped. Besides getting a different motherboard, not sure what else I can test.
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coilz wrote: A slight update. I switched my i7 8700K ( a different CPU then the suspect one ) into the MSI board coupled with the 120mm AIO. Does not experience temperature difference like the other CPU. Thermals are also more under control with only 5C difference between highest cores and lowest cores which is more " normal" . Temperature does not get much higher than mid 80s even after a 10 min Cinebench R23 run, which I think is expected from a 120mm AIO. With the problem CPU, 2/6 core will get to 100C and throttle.

I've mounted and remounted the Coolers so many times now testing various combinations. Maybe the MSI board just doesn't like the original i7 8700 non k?.... I am stumped. Besides getting a different motherboard, not sure what else I can test.
Where did this 8700 non-k come from? If you recently purchased it, the previous owner might have fed it a few too many hot suppers. If so, the suggestion of delidding isn't the worst, but be aware you could pretty easily destroy your chip.

Have you tried to update BIOS? Generally can't hurt, and with all the changes to schedulers, microcode for spectre/meltdown/etc, maybe there's an optimisation you're missing (or, more accurately, an optimisation/compatibility that the 8700k has that the 8700 non-k doesn't). Also, does your motherboard have multi-core enhancement? If so, try turning that off.
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ChubChub wrote: Where did this 8700 non-k come from? If you recently purchased it, the previous owner might have fed it a few too many hot suppers. If so, the suggestion of delidding isn't the worst, but be aware you could pretty easily destroy your chip.

Have you tried to update BIOS? Generally can't hurt, and with all the changes to schedulers, microcode for spectre/meltdown/etc, maybe there's an optimisation you're missing (or, more accurately, an optimisation/compatibility that the 8700k has that the 8700 non-k doesn't). Also, does your motherboard have multi-core enhancement? If so, try turning that off.
The Chip was bought used from FB marketplace from a part out. Might have lived a hard life before. I am hesitant of delidding since like you say theres a chance i could destroy the chip and I'll have to invest in the tool .

I've updated the bios to the latest version, same issue. Will look thru the bios and see if theres anything that'll change the temperature behavior. Although I do believe its a combination of mounting and the board's back plate. I notice the back plate thats attached to the socket is of a different variety than the one on the Asrock board. The MSI board's plate has a minor beveled border while the Asrock one is flat around. Perhaps its enough to mess with the mounting pressure ? Just hypothesizing here.

Anyways, after working a few more trial and error tests, I've gotten the temperature under 90C with the 120mm AIO. Achieved it by adding a little more thermal paste on the "left" side of the CPU. Can get thru a 10 min cinebench run at around 90 in highest core temp which is an improvement of throttling at 100C. There is still noticeable difference between the highest core and lowest core of ~10C, but as long as its not throttling I am content.

Maybe its a combination of uneven IHS and incompatible mobo/mounting type. Or I could try to paint thermal paste on the whole IHS method, although that creates a big mess if I ever need to remove the cooler.

Before anyone suggest I am mounting incorrectly with my normal technique... I mounted the D14 back on the i7 8700k and Asrock board, blob of thermal paste in middle , temperature just fine barely breaking mid 70s on 10 min cinebench run.
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Have you compared the voltages between the MSI & Asrock? Could it be that the MSI is giving out a higher Vcore? That could be the reason for the overheating. In which case, slightly under-volting the CPU should get it working correctly
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Yeah, use the Intel Extreme tuning utility and try undervolting like suggested. I'm running my 10700k at minus .1v and the temp drop is noticeable.

Also, deliding is not really that dangerous with the kit.
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Slight update. So the computer has degraded from performing pretty normally, to intermittent reset, to not booting into windows. Currently have taken it out of case back on cardboard box with no video card and one stick of ram. Tried reinstalling windows, hangs before even getting into windows, can't even get into safe mode. Tried with 2 different SSDs. Tried with 2 sets of DDR4 ram, different slots. 2 Different power supplies. Tried installing windows with and without video card, same issue. Just hangs after the first installation reboot, hangs at the same spot everytime. Left it for 30 mins and nothing. Windows will install off new USB media, but hangs after the restart.

Have also tried bumping the BIOS version down one from newest. No go.

In the end.. either CPU or Motherboard issue ? This was suppose to be a cheap build ! :( Ordered an Asus B365M motherboard off amazon and lets see how that goes.
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Sounds like the mobo to me. Do other CPUs boot on it?

The windows hang sounds like it tries to initialize something and that fails. So it hangs.

Have you tried safe mode or a Windows PE disk? The device manager may report what is failing
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kramer1 wrote: Sounds like the mobo to me. Do other CPUs boot on it?

The windows hang sounds like it tries to initialize something and that fails. So it hangs.

Have you tried safe mode or a Windows PE disk? The device manager may report what is failing
Couldn't even get into safe mode when it hangs. and yes, other CPU does boot on the MSI board.

Played around with it a bit more today. I noticed the Date in the BIOS is set to year 3221, switched that back. Played around with the PCIE Gen X setting from Auto to 2 and 3 (no idea why that would do anything since i was using the IGPU). Turned fast boot and secure boot off. Not sure which combination of things did it , but was finally able to install windows on the original SSD i had in it and it successfully went thru first restart after installation and get into the desktop.

It's just weird all around. Put 2 sticks of the original ram I had back in... kept working. The power supply that I thought was causing random resets... kept working. Put it back into the case and it works... Hooked up the RGB fans and it works. Even installed MSI Mystic light and it works. I even installed a Radeon 7950 in there so it had a graphics card and that seemed to work as well. Super stumped as to what the issue was in the first place. So now i am back to the just the temperature is a little bit high. Going to run it as my main rig for a few days and see what happens. It's like I gone full circle. I might still switch the motherboard to the asus I have coming in since I have no confidence in the MSI one at the moment.

Posting from the suspect computer right now...
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That date seems just weird enough to have triggered a bug somewhere. Or its the mobo.

Often old mobos have corroded copper traces. If you move them, plug unplug components, it stretches the mobo and they start working again.

How old is that MSI?
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kramer1 wrote: That date seems just weird enough to have triggered a bug somewhere. Or its the mobo.

Often old mobos have corroded copper traces. If you move them, plug unplug components, it stretches the mobo and they start working again.

How old is that MSI?
Its a MSI B360 pro gaming. So probably around 3 yrs old max. Again its a used part from some guy that upgraded.
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coilz wrote: Its a MSI B360 pro gaming. So probably around 3 yrs old max. Again its a used part from some guy that upgraded.
Then it makes absolute sense. I am 99% sure it is a dying mobo. That is all. That explains a lot of intermittent behaviours, not booting, being weird in general. These are all signs of mobo failure. Nothing will make sense and you'll want to pull your hair out in frustration.

MSI boards normally cheap out on the copper and have often given me trouble in the past. Gigabyte and Asrock have been amazing though
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kramer1 wrote: Then it makes absolute sense. I am 99% sure it is a dying mobo. That is all. That explains a lot of intermittent behaviours, not booting, being weird in general. These are all signs of mobo failure. Nothing will make sense and you'll want to pull your hair out in frustration.

MSI boards normally cheap out on the copper and have often given me trouble in the past. Gigabyte and Asrock have been amazing though
Nothing makes sense for sure... its been running smoothly today. Blasting it with Unigine Valley and Cinebench R23 on loop in the back ground and no hiccups.
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Ok got the Asus B365M Motherboard in. As expected, the temperature readings are tighter with highest/lowest core 5-10C difference. Where as the MSI board is 10-15C difference. I do notice that the Clockspeed is more consistently higher on the MSI , can sustain a 4.1-4.2ghz clockspeed over a 10 min Cinebench R23 run, where as the Asus will clock down to below 4ghz. So I would say @kramer1 is correct that the MSI runs the cpu at a higher clock speed more frequently. The MSI B360M gaming plus doesn't have much multicore tweaking i can do , and I am leaving all the power loadline settings on auto for sake of simplicity. Will run the MSI build for a few more days and see what happens. Probably keep the Asus board around as back up or for a future build.
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Throw the MSI. Not worth wasting your time with a 3yr old board

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