I have questions regarding the behaviour of my 2950X.
It is cooled by the NZXT Kraken X72 AIO. When under load, the die temperatures quickly rise to almost exactly 68 C and stay there, while to coolant temperature slowly rises and eventually stabilizes around 44 C.
I believe this temperature is the thermal limit of the chip for PBO which tunes the clock speeds so that the chip does not exceed it. Is this true? Is it normal for a well-cooled chip to be running steadily at this temperature, or do I have a cooling problem? I am not sure how exactly the PBO algorithm works, but does this behaviour mean that the chip is bottlenecked by the cooling solution and would run faster were I to improve it?
The clock speeds vary by workload, but for example during an mprime small FFT run, they stabilize at around 3.6 GHz.
3.6 sure seems like throttling is going on… I easily achieve 4ghz all core on my 2950x using PBO and a cooler Master TR4 AIO (has the large TR4 cold plate).
I haven’t tried pushing it harder, it’s a server more than a workstation.
Interesting. What kind of workload gives you allcore 4GHz? Mine can do that on some workloads as well, but small fft prime95 is essentially a power virus.
Does your chip run at the 68C mark or lower?
According to lm_sensors I’m at 27c right now, but my ambient temperature is only 15c so there’s that.
No workload in particular, I am running “tuned” on Linux and have the profile set to performance-throughput for a virtual/server workload. I haven’t run any stress tests on the machine since I built it last spring and tried using it as a desktop. According to cpuinfo all my cores are running at 4.0ghz roughly.
You are at 27 C under load? My idle temps are slightly below 40, but the ambient is much higher than yours, maybe about 25, not quite sure.
You cores are running at 4GHz, but are they actually doing anything?
While i have a 1950x instead of the 2950x i can be under that 68c mark at 4.0ghz with the same cooler master cooler as gordonthreee. If you really want you could try getting a new tr4 specific cooler and do some testing to see if your clock speeds go up 3.6 all core seems a little low.
Yeah that’s what I will probably end up doing. I just wanted to verify whether it’s actually a problem or expected behaviour. I wondered whether the chips always run at 68C regardless of cooling (other than something outlandish like ln2) and just tune the clocks the highest they can, while remaining within the thermal budget.
Yeah, 3.6 GHz sounds low, but again, it depends on the load. Some loads run at 4 GHz, but they don’t even reach the temperature limit. A linux kernel compilation ran at somewhere between 3.8 and 3.9 GHz.
My chip can go into the 70’s if im pushing the 1080ti and 1080 at 100% so i dont kno of there being a 68c temp limit. I do remeber reading somewhere that 64c was the preferred 24/7 temp to not go above but i do not believe they are limited to 68c i could be wrong tho.