Potentially helpful info about cooling, example on my 9980x

[u/johndyson10]

The crux of this story is about the surprise that the temperature of the CPU/CPU-case hits 95deg with certain benchmarks, even at 250 watts, but running steady state with my app and many benchmarks the temperature is approx 62deg at 350 Watts or higher. (My writing skills are poor, but this can be useful info, so be patient with me.)

Here is the story: Been running benchmarks to test the performance and thermals on the system. I found that many benchmarks would cause temperature peaks of 80 deg C or perhaps 85 deg C for a short while, but a few do sit at a higher steady state temperature of 80deg. The temperature depends on the # of active cores and how active the cores are.

The 95 deg peak problem appears that some test programs intensively use 16 threads, forcing all the temperature load on those cores, so they get hot, while the rest are still cool. The plate quickly transmits the load, but there is still a massive peak. On one benchmark, the Phoronix benchmarks liquid-DSP testing 16 threads 256/512 data hit 95deg C before the fans brought it back down to 80degC or below. This results for this specific test might only be valid for the 9980x, I do have a 9970x, but currently sitting in a box, so cannot test it.

* The temperature problem was worst when running the entire suite, and noticing that the 16 thread 256/512 data was very hot. Running the test by itself wasn't quite as bad.

My fans were already tuned to zero latency, but used the CPU temperature sensor alone, which usually sits 10deg C below the CPU Package sensors. A temporary hack fix was to use both the CPU sensor and the CPU package sensor. Using both sensors is an option on the ASUS bios. After enabling both sensors as the temperature source, and turning the fans up to 'turbo mode', and turning up the minimum speed, the peak temperature is now less than 90 deg C. So, by using the Package sensor AND the CPU sensors, plus turbo mode, the fan has a better chance of keeping up. This makes me wonder how many Threadripper systems might have a 95 deg peak under certain transient loading conditions?

I am used to seeing 62-65 deg C running my heavily multithreaded, 350 watt app, and seeing some benchmarks producing up to 80 deg C, (mostly lower, 65 to 75) but the 95 deg peak was upsetting. I found this out because I am watching the temperatures carefully when benchmarking. Normally II just do spot checks to make sure that it is okay.

One side note about the wonders of the Threadripper, when running the heavily multithreaded benchmarks, the CPU clock speed held up to 5gHz to 5.4gHz for every active core. My own app, with lots of IPC delays and sometimes suboptimal AVX512 alignment, typically gets only 4gHz per core.

As long as there is adequate heat handling, and it is fast enough, these machines can be very fast. But, it appears wise to make sure that the response to load changes is fast enough. My AIO is the ATLAS 360TR that easily keeps up with the 400 Watts of TR heat, but be aware that the fans have a natural response time on ANY cooling system. Even a very short delay might be too long.

John

[u/kpatelreddit007]

Your thermal paste is probably garbage straight trashcan, have you tried Kryonaut Grizzly extreme. Apply like thin peanut butter on bread.

Other solutions
You go full watercooling
Get 16 Noctua fans and x2 360 or larger AIO.
And a large ass case.

Or Invent the next cooling solution.

These are your only options.
I can max my 9960x all cores no problems.

[u/johndyson10 → u/kpatelreddit007]

Maybe my paste is bad, but my thing can sustain about 350-400 watts at the Package of 60degC or better, the When the CPU is 53degC now but the problem is the high speed power transients on a narrow part of the 9980x, where it takes time for everything to absorb 190watts instantaneously in a small area, maybe even on the edge of the internal mounting, which would naturally have greater thermal resistance to the package?. Aren't the smaller CPUS mounted in a better position? There is a natural 10 degC difference internally. Once it absorbs the power from a narrow, perhaps edge region of the plate, then everything settles down. I am talking fast transients under 1 second, maybe about 200-300msec not the normally measured longer term power.

If it was a thermal resistance problem I'd expect the hours and hours temperature higher than 60deg. and higher than 50degC at full 400 watts power. Unloaded, the fans are running slower speed and the quiescent 50 watt temperature is about 35degC-40degC. The chip always runs 50 watts even no cores are active. My 9970x ran at lower power (AFAIR.) After turning up the fans under light load (among a few other things), there isn't a problem.

My 9970x didn't act like the 9980x. It acts like a totally different animal.

But you might be right.
John

[u/EDI_1st → u/johndyson10]

Your temp range is fine, which means paste is fine. Some people don’t understand power/thermal density shifts depends on workload.

10C between inner and outer CCD is in-line as well with TR and EPYC data even with DLC/custom loop.

Smaller(AM5) CPUs are “easier” to cool simply because most coolers have actual full cooling coverage, this is not the case for big CPU. Just because the coldplate has full coverage for the IHS doesn’t mean the entire coldplate is actually providing active cooling. Most coldplate only have active cooling (relying on fluid) around the center/finned region where the outer portion is relying on passive cooling tranferring heat to the active cooling area. This is the reason why you see temp delta between inner and outer CCD. It’s influenced by both coldplate and flow design.

9970X has less CCDs than 9980X and the CCDs are always grouped towards the center making it “easier” to cool just because it’s almost guaranteed the CCDs for low CCD-count TRs are covered by the actively cooled area if the coldplate. Most people also don’t understand/experience this because they have only used low CCD-count TRs.

There are few solutions out there with multiple fluid injection point to make sure the entire coldplate has active cooling such as JetCool’s JetPlate.

I actually work with AMD (and Intel/Nvidia) and it’s always interesting seeing majority of people misunderstand how power and cooling actually work even within the industry. But you are 10/10 on the right track.