Insane CPU usage and temperatures while exporting

Help/How To
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I just joined this forum ^^.
I can see people have asked questions related to this particular topic but I couldn’t find any tending to my concerns. Sorry if I missed any

While exporting videos my CPU ( intel core i5) goes to 100%, which, I saw from other answers, is normal. But my CPU temperature (according to MSI afterburner) shoots from 35-40°C up to about 97°C, if not more, in the span of 2 to 3 seconds, and similarly, in a couple of seconds, drops back to 35°C as soon as it is done. I would really like to not completely fry my CPU and would love to know how I could make this better, as in should I invest in a better CPU or a better cooler?

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Your CPU is probably not in danger because Intel CPUs have temperature based throttling. The throttling is triggered when the CPU reaches the maximum junction temperature. This threshold varies by model but is usually somewhere around 100C.

Regardless of damage risk, you are almost certainly not achieving the maximum performance of your system. Look for a better cooling system to see if you can get the temperature down and avoid the clock speed throttling.

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Ok. Thank you, that helps a lot. I really appreciate it ^^

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If your processor heats up to almost 100 degrees, I would recommend that you change its thermal paste and clean the cooling system, otherwise the processor may deteriorate ahead of its time. To lower the temperature, you can also use undervolting. But you also need to understand that sometimes temperature sensors can lie or programs can not read them correctly.

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You can also make Shotcut export use less CPU by turning off Export > Advanced > Video > Parallel processing and then also in Export > Codec, set the number of Threads somewhere between 1 and your CPU thread count.

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I’ll look into that too. Thank you ^^

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Hi, Long time user of SC, but first post here. This topic raised by Teek Tak describes my recent experience too. Thanks for the further contributions, esp Shotcut (Leader) which are all helpful.
Being new to a PC with i5 with 20 processors it was a shock initially to see temps rise quickly to 90c+ and sometimes to 100c on several of the processors. So this chimes with me, and have done much SC processing to learn and evaluate what to do about this, or at least how to cope with it.

I see 3 areas to look at:

  1. CPU cooling is the obvious one (but not a silver bullet). My i5 Spec shows max power dissipation of around 150W (I’ve seen 170W reported by monitoring s/w) beyond which it self-protects by throttling mechanisms, and my current CPU Fan is rated at 150W (dissipation/cooling effect) ! The next model up is twice the weight and rated at 200W. As an electronics hardware person I’d be happier to upgrade to this to provide some headroom to the CPU’s cooling requirement and hopefully lower its operating temperature overall, even if by just a small amount.

I’m keeping track of the CPU Fan’s RPM as an indication of when the Fan cooler is maxed out - it can be with PC CPU Resource of 33% upwards but with CPU core temps of 75c and upwards.

Having a modern BIOS was a revelation to me, but I’ve been pointed to the Fan Profile area (in BIOS advanced settings). In here options allow quiet running, Turbo (faster Fans, a little more noise) or continuous Full Speed (not tried that yet!).
Some i5 variants have (automatic) Over Clocking to squeeze out more performance (and heat !!) If so, the BIOS should be able to disable this, giving you some control.

  1. The most alarming fact is the very quick rise in CPU temp as Apps demand processing resource. SC in reverse playback (Frame by Frame) is one example, and in Photoshop even when changes are made to individual parameters in real-time (eg applying Unsharp or DxO adjustments) the cooling Fans kick in immediately the adjustments are being made to cool down the instantaneous temp rise. What is reassuring is that these new Processors have in-built protection, so have mechanisms to invoke thermal throttling and are therefore self-preserving.
    But keeping out of this area of operation is still a good thing overall. At the moment I’m aware of the Fan speeds changing as I work at the PC ! but I’d prefer to concentrate on the screen.

The effects of instantaneous increase of CPU temp will not be simply cured by a larger Fan assembly, but by an increase in mass of the metalwork in contact with the CPU itself. For my CPU Fan, the weight of the assembly doubles with the next model up (575g > 920g) but it looks like the metalwork interfacing with the CPU is increased in its mass, looking at the photos of it. It may not be much, but there’s no time to wait for the heat to be transferred to the heatsink then removed by the Fan, you need a good thermal mass (already at a cooler temp) at the CPU surface.

  1. User related: PC Resource as required by Apps in use. Obviously SC requires lots of processing when ‘busy’. I’m grateful to Shotcut (Leader) for pointing out the (crude but welcome) control by disabling parallel processing when compiling/Exporting an output file.
    Even before Exporting, a Fast Playback in reverse, with Filters applied, is a big processing task which raises the Resource needs and CPU temp can easily rise to 95c+ with CPU dissipation of 140-170 W. Although to be fair, this was with an Export running too. I just wanted to multi-task whist the PC was otherwise ‘busy’.

I had hoped that with my new PC I could run 2 copies of SC and compile/Export simultaneously, to double up the batch processing I do and maximise the power of the processor. Yes, you can do this, but all of the above applies twice over ! The PC processor is thermally limited !!

[PC h/w monitoring s/w used is CPUID HWMonitor (simpler) and HWiNFO64 (includes averaging & logging) and indicates if throttling has occurred ]

[CPU Cooler is Be Quiet BK007 Pure Rock 2 Black CPU Cooler (150W) will try BE QUIET BK021 Dark Rock 4 (200W) ]

Thanks again to the SC Team for a great s/w package ! and the upgrade to i5 means I don’t have to use Preview Scaling, or Proxy Files.

Ken

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