HP Z6 G4 Workstation, Second CPU Temperature high

[CoolTom]

Hi, I got HP Z6 G4 Workstation With CPU riser board for second CPU and it has the standard config with 2 x Xeon Silver 4112 CPUs. I did upgrade both CPU to Xeon Gold 6152. This CPU has TDP 140W.

https://www.intel.com/content/www/us/en/products/sku/120491/intel-xeon-gold-6152-processor-30-25m-ca...

Base on the docu for Z6 G4 the max TDP for CPU is 205W and when it reach 165W it can accomodate just one CPU. Mine has 140W so all should be fine.

The second CPU on riser is running cca 25C higher, than the one on system board. Without load is not that critical, but under 100% load/stress test the mainboard CPU run around 70C (package) and the second CPU on riser board run at 90-95C (package) and start throttling. 

Max Package Temp for this CPU is 92C.

The raiser board has 2 FAN. One take in (CPU+RAM) and one smaller take out. Base on HP Performace Adviser application both of this FAN run much higher than the mainboard CPU fan. Raiser cca 3000RPM and main like 800RPM.

I did repaste thermal paste twice (Thermal Grizzly) and whole cooler on raiser board is HOT - so it seems like it is transfareing heat correctly.

Any idea what can be the problem and how to cool down second CPU?

[V15MYassin]

Check the thermal paste for the second CPU it would cause such an issue. 

[CoolTom]

Hi, thank you for reaction. I did use Thermal Grizzly thermal paste. When i did the stress test i remove the heatsink and the paste was nicely placed on whole surface of the CPU. I repeat it and temperature was still same bad. Tho whole heatsink was very hot so that also make me think the paste is fine.

Also intake fan - on picture it should be Memory fan2

and

outtake fan - on picture CPU1 fan

and

outtake realr chassis fan 

are all on high RPM and you can feel realy hot air from back of the computer (realr chassis) - all this make me think, that heat is taken from CPU correctly ...

[V15MYassin]

Check the fan itself, and make sure that the air flow has no clog, and make sure that the second CPU tray is properly installed. 

And do you use a GPU card? 

[CoolTom]

Check the fan itself - this is not easy task as everythink is boxed in plastic. What i see the intake fan is after the hard drives cages - but i didnt instal any 3,5 HDDs yet, so its as open as HP design allow - and both FANs are running ... you can see and hear it and also feel hot air flow on outtake site

GPU - i didnt instal GPU yet - just CPUs and RAM sticks

 

[V15MYassin]

If the rear side fan is working as well, then I'm clueless. 

[CoolTom]

@V15MYassin ajaj. Yes rear fan is working. Is there any chnace, that the CPU is faulty? Like work fine just heat more than usual?

[V15MYassin]

In my Z620 I can control the system fans speed. Check if you can increase the fan speed to fix that issue.

[CoolTom]

I did switch CPUs from Raiser i put it into main socket and from main socket i put it in raiser.

Now the main CPU is hotter then the one in raiser - is it possible the problem is in one CPU - bad internal cooling.

When i run same CPU and not install raiser it seems to be fine, but with raiser hot again. See screen shots

1 CPU mainboard iddle and stres test

1x Main board CPU IDLE1 Main board CPU STRESSTEST

2x CPU - with raiser - IDLE, 8K video youtube, stresstest - main CPU same, like in 1CPU tests

2x CPU - IDLE2x CPU - 8k video youtube2x CPU - stresstest

[EastoftheBay]

I have the same problem.  I have two xeon gold 6154.  I've first noticed the issue when the second CPU's fan went psycho on an app, and the whole computer froze.  I had to power down.  The same issue repeats a couple times before I suspect that there is some underlying overheating dilemma.  I installed HWmonitor and noticed right away that the temperature of both of my CPU are low's 50 to high 60's without any significant computations.  I attempted to do a multicore run with Cinebench R23.  Needless to say, the computer froze within seconds because the second CPU's temp was higher than 104.  I've reseated the second CPU.  I applied new thermal paste.  Both did not significantly alter the temperature.  I wanted to increase the fan speed.  I installed fanspeed/speedfan but they did not recognize the fans in my HP.  I went into Bios and noticed that idle fan speed is set at 0.  I changed that to 35% more than baseline.  Right away, I noticed that CPU temperature ranging between low 40's to low 50's.  Even at 35%, the system still crashed two minutes into Cinebench R23 multicore testing.  I increased the idle fan speed up to 50%, and repeat the same test with Cinebench R23.  The system did not crash but the temperature of the second CPU did reach 100.  The issue with increasing the fan speed is that the machine is loud.  At 35%, it was noticeable, and at 50%, it was a jet engine.  I changed the fan speed down to 20%, and live with it knowing that if I ever want some serious power, I might have to up the ante with the fan speed and deal with the noise. 

I think this is a design flaw; the fan for the second CPU is inadequate.  I am certain HP is aware of this issue.  The new HP Z6 G5 does not come with a second CPU, only the Z8.  I am considering purchasing a bare-bone HP Z8 G4 and transfer all the other components over, or I might just sell the riser and second CPU.