Chaos Corona for Cinema 4D > [C4D] Daily Builds
Mac M1 LOW POWER MODE bug lives on.
YURII:
Sarcasm here? It will be same result
--- Quote from: James Vella on 2023-02-19, 22:17:43 ---
--- Quote from: YURII on 2023-02-19, 21:28:55 ---So, I did a Cinebench R23 benchmark just now (16", M1 Max, 64RAM), started with Low Power mode, ran it for 10:00:00 and the score was 10834, then, immediately, after this test, I ran it again, this time in High Power mode and **SHOCKER** it scored 12108.
--- End quote ---
Interesting! Can you try a 60 minute test and post the results?
--- End quote ---
James Vella:
--- Quote from: YURII on 2023-02-20, 06:37:21 ---Sarcasm here? It will be same result
--- End quote ---
Not sarcasm, just genuinely curious. It would be a good way to test/compare the throttle theory.
TomG:
YURII, as has been explained multiple times, 100% CPU is not the same thing, it all depends on which parts of the CPU software is using. Corona drives the CPU harder, or some parts of it, or makes the CPU require more consistent draw of power, than other software. It's as simple as that - the fact that some high level approximation says "100% CPU" does not mean you are comparing apples to apples.
Corona is known to use the CPU in a much more demanding way - ie taking full advantage of what the CPU can do - than other software, because we are so well optimized to use the CPU to its full advantage for rendering. Again, the evidence is in the fact that a 2 minute render on high power will run faster than a 2 minute render on low power mode, but after 5 minutes suddenly everything drops in speed - which can only be thermal throttling of some part of the motherboard or CPU. This then comes down to the design not being able to keep everything below throttling thresholds when the CPU is exploited so well.
This is not unique to Macs - if a PC had inappropriate cooling on it, it would do the same. If a motherboard had inappropriate cooling in any machine, it would do the same. It is impossible for software to ask a CPU to do more than it was designed to do - but it's entirely possible for a cooling system or motherboard design not to be able to support the CPU doing its maximum for an indefinite period.
So again, there is nothing we can do other than "cripple" Corona to NOT use the CPU to its best advantage - which you can already do yourself, with less threads, or low power mode.
I really don't know how else to explain it, so I guess if you choose to believe otherwise and have some explanation for why high power mode works at high speed for a period of time then slows down, then we will have to leave you to that belief.
TomG:
"you guys don't even have your own set of M1/M2 Macs to test all these hypothesis in house." - it has been answered already that we have access to the machines to do our own testing in house.
"Doesn't happen with other software" - other software doesn't access the CPU in the same way as we do. e.g. on my PC when denoising kicks in, I can hear my fans increase in speed, because it is known that denoising fully exploits the CPU more than anything else I have on this machine, with no spare clock cycles where the CPU gets any chance to cool down for microseconds. Remember, it's not just using the CPU, it's what parts of the CPU, and how consistently they are used without breaks, gaps, or pauses. Every software is different (but in the high level, approximate / summary, all will still say "100%" even though that represents different access to the CPU).
TomG:
"crippling it by setting Mac to 'Low Power mode' gets better results than by using your very optimised algorithm, does it makes sense?"
No, for short renders (before heat has time to build up), Low Power will be slower, as expected. After a period of time where the CPU working so hard causes heat to build up, performance will drop as thermal throttling kicks in. Your 2 minute render will be faster in full power mode, in fact every render up until the CPU or motherboard hits the thermal threshold will be faster. For the render time after that, performance will be worse than low power mode, meaning that for long renders you may be getting a better average performance with low power mode vs. high power mode for a time then thermally throttled performance after that time.
Again, this change in performance after rendering for a period of time is what points to thermal throttling - if it was poor optimization, high power performance would be worse even at the first few minutes of rendering.
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