Author Topic: Custom cooler mount  (Read 5171 times)

ejfluhr

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Re: Custom cooler mount
« Reply #15 on: September 11, 2023, 09:12:02 pm »
>For stability testing I ran this machine hard for multi-day cycles (one of my own tools that 100% loads the CPU cores with lots of maths).

Do you know how "hot" that workload is compared to the TDP rating of the processor? 

Regards, Eric

Woof

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Re: Custom cooler mount
« Reply #16 on: September 12, 2023, 05:06:04 am »
I don't, but when comparing the exact same test with the IBM 3U HSF the temperatures were around 70 degrees.

I have a replacement mobo now (RCS were really helpful here) and I'm waiting on some CNC'd parts back with amends to make installing this easier. The design files are here for anyone interested:

    https://github.com/cwoffenden/talosmods/tree/main/am5-sf2-cooler

(I'll be updating this and adding docs along the way)

ejfluhr

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Re: Custom cooler mount
« Reply #17 on: October 04, 2023, 06:52:40 pm »
Seems like you have an 18c POWER90 rated at 190W?   https://raptorcs.com/content/CP9M36/intro.html

POWER9 TDP long-term max temperature rating is 85C.  If your system runs ~70C, you have decent margin to the reliability limit.  How much is the improved cooling and how much is your workload would probably need to come from power data vs. that 190W spec.




Woof

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Re: Custom cooler mount
« Reply #18 on: October 05, 2023, 09:47:52 am »
Yes, I have the dual 18 core, and with the water cooling temps are around 40 degrees (same as the simpler solution from Vikings) and the machine is running silently (a quiet machine was the original aim). The same tests with a Noctua air cooler the temps are mid-50 and the fans are quiet (compared with the IBM HSF, anything is quiet).

We water cool racks of machines at work, with the big benefit being keeping the temps down keeps the clocks high and the power consumption down. With Threadrippers, for example, they run at boost clocks all the time, vs down-clocking to half the speed to stay within TDP, effectively doubling the throughput. Same with GPUs (which is where we do most of the water cooling, CPUs was just a curiosity).

Real life took over for a while but I will work on a jig to test the mounting pressure.

ejfluhr

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Re: Custom cooler mount
« Reply #19 on: October 09, 2023, 06:43:39 pm »
>with the big benefit being keeping the temps down keeps the clocks high and the power consumption down.

If using IBM's WOF, the algorithm does not work that way.   It should boost to "the same" frequency regardless of CPU temp until it exceeds the temp limit at which point it will lower frequency to protect temperatures.  The TDP is conservative and very few workloads would exceed that.   The bigger factor affecting the temp protection mechanism is ambient temp....> 30C is more likely to throttle than < 30C.

What workload are you testing with?   I just got a Blackbird running Ubuntu and am stress testing it to see how it responds.  It's quite fun.

Woof

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Re: Custom cooler mount
« Reply #20 on: October 14, 2023, 10:53:27 am »
Thanks for the info, I know little about how the IBM WOF works.

The workload I'm testing with is from a graphics tool I've been working on for a while, which is interesting because I'd tuned the threading for 64C/128T Threadrippers and then started using it to compare other systems (and it's a nice workload for many cores). Send me a PM if you're interested in building it from source, I'm not ready to announce it yet so it's under wraps (GCC/Clang and CMake on most systems build out of the box).

MPC7500

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Re: Custom cooler mount
« Reply #21 on: October 14, 2023, 07:05:22 pm »
For the Threadripper, have you tried this?
https://github.com/tud-zih-energy/FIRESTARTER

POWER9 support is planned

Woof

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Re: Custom cooler mount
« Reply #22 on: October 15, 2023, 06:57:06 am »
I haven’t seen that but I definitely will try. A quick look at the source and I see it’s handling thread affinity, a requirement for Threadrippers on Windows.

ejfluhr

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Re: Custom cooler mount
« Reply #23 on: October 20, 2023, 09:49:36 am »
That looks interesting but
>We therefore use highly optimized assembly routines that take the specific properties of a given processor microarchitecture into account.

Is that what is being done for
>POWER9 support is planned
??


I'm running a mersenne-prime calculator which seems to push the CPU pretty hard.  At least, it runs down near the "base" frequency of 3.2GHz (I have a 4-core CPU).

>cat mersenne.c
#include <stdio.h>
#include <stdlib.h>
#include <gmp.h>
int main(int argc, char *argv[]) {
   char *endptr;
   unsigned long int p = strtoul(argv[1],&endptr,10);
   mpz_t M, powerof2, one, two;
   mpz_init(M); mpz_init(powerof2);
   mpz_init_set_str(one,"1",10);
   mpz_init_set_str(two,"2",10);
   mpz_pow_ui(powerof2,two,p);
   mpz_sub(M,powerof2,one);
   gmp_printf("%Zd",M);
   return 0;
}



Run with:

>cat mersenne16.ksh
num=82589933
thread=0
while (( thread < 16 ))
do
   echo $thread
   echo time ./mersenne $num > M48.$thread
   time ./mersenne $num > M48.$thread &
   (( thread += 1 ))
done


« Last Edit: October 20, 2023, 10:24:43 am by ejfluhr »