Temperature outside is not normal for Central Europe summer(31 degrees of Celsius) but I meat temperature on the BlackBird chips. The system is meant to be small (miniATX) and the default heat sink is passive, without the fan. My computer case is the Fractal Design CORE 1100 with one 120mm fan. I added a second 120mm one (it can be mounted on the side of the case – it’s located over Blackbird’s PCIe slots not over the CPU) and the results were not satisfying as usual CPU temperature was over 80 degrees of Celsius. It seems to be normal but I am not sure if it isn’t too much. And I am not sure what maz happen if the system will be under continuous load.
The case manual suggests that I can add a 80mm or 92mm fan to the back of the case. The 120mm one does not fit here. But the manual also says that I have to use or two 120mm fans (in the front and on the side) or two 92mm ones (onth the front and at the back of the case) and do not mix them. At the moment I the default 120mm one (front fan) and the new 92mm (at teh back) ad waiting for the second 92mm one.
The temperatures are about 75 degrees in idle and over 85~87 degrees under load (I use Fedora 30 with the MATE and CPU governor is “ondemand”). Most time I use a WWW browser, the Vim, some office tools and so. I’m running the LaTeX or the GCC randomly but not so often. So (except the Firefox) the system is not so much loaded (just now).
So I tried to play with the system a bit (help for tah is here). I changed the governor to “powersave”
# cpupower frequency-set -g powersave
And do I need all 16 threads? No, 4 should be enough for now. So I allowed just one thread per CPU core:
# ppc64_cpu --smt=off
Well, and do I really need all FOUR cores? Two should be enough:
# ppc64_cpu --cores-on=2
And now the temperature is 70~73 degrees for all time. And the system is still fast enough. And when I will have to to something bigger the I will set the “ondemand” or “performance” governor and make all 16 threads available.
But I’m going to test the new fans setup first…
Jirka's notes 