Topic by Cifer

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Topic: CPU load about 10% for every core but audio load maxed

Hello everyone,

I'm trying to understand why the audio load displayed in Pianoteq is constantly at the limit when I select extremely low buffer sizes like 8 samples, while the cpu barely has to work. One explanation I've read is that the CPU load in Windows updates more slowly than the audio load bar in Pianoteq and my simply not show the spikes.

However, in my case, even if I use the lowest possible settings so that the bar is completely red while I play (imagine a red rectangle) and keep playing for an entire minute, the CPU doesn't show a single spike above 20% for any core.

Another observation I've made is that certain settings play perfectly without any crackling even when the bar is constantly maxed out, while others crackle even when the audio load is very low. I don't understand this at all.

What is going on? Is what limits the audio load a capacity of the CPU that's not reflected in the CPU load? Or is Pianoteq somehow underutilizing my CPU?

Thank you!

Last edited by Cifer (09-12-2022 21:19)

Reply by Antonio M

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Re: CPU load about 10% for every core but audio load maxed

Cifer wrote:

Hello everyone,

I'm trying to understand why the audio load displayed in Pianoteq is constantly at the limit when I select extremely low buffer sizes like 8 samples, while the cpu barely has to work. One explanation I've read is that the CPU load in Windows updates more slowly than the audio load bar in Pianoteq and my simply not show the spikes.

However, in my case, even if I use the lowest possible settings so that the bar is completely red while I play (imagine a red rectangle) and keep playing for an entire minute, the CPU doesn't show a single spike above 20% for any core.

What is going on? Is what limits the audio load a capacity of the CPU that's not reflected in the CPU load? Or is Pianoteq somehow underutilizing my CPU?

Thank you!

Before anything else make sure the CPU scheduler/governor is set for "Performance", not "power save", might not be that but it's a simple thing to try.
(I don't know the exact terms for Windows or how to set that.).

Reply by Cifer

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Re: CPU load about 10% for every core but audio load maxed

Antonio M wrote:
Cifer wrote:

Hello everyone,

I'm trying to understand why the audio load displayed in Pianoteq is constantly at the limit when I select extremely low buffer sizes like 8 samples, while the cpu barely has to work. One explanation I've read is that the CPU load in Windows updates more slowly than the audio load bar in Pianoteq and my simply not show the spikes.

However, in my case, even if I use the lowest possible settings so that the bar is completely red while I play (imagine a red rectangle) and keep playing for an entire minute, the CPU doesn't show a single spike above 20% for any core.

What is going on? Is what limits the audio load a capacity of the CPU that's not reflected in the CPU load? Or is Pianoteq somehow underutilizing my CPU?

Thank you!

Before anything else make sure the CPU scheduler/governor is set for "Performance", not "power save", might not be that but it's a simple thing to try.
(I don't know the exact terms for Windows or how to set that.).

It's always set to maximum performance. It doesn't matter either way because what energy saver mode does is lower the frequency and potentially throttle the CPU. In that case the CPU load would be higher. My issue is that the CPU load I see is very low while the audio load is maxed out.

Last edited by Cifer (09-12-2022 21:19)

Reply by groovy

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Re: CPU load about 10% for every core but audio load maxed

Have you seen the pop-up help?

https://i.postimg.cc/fyRC1CKB/audio-load-8-0-3.png

Reply by Antonio M

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Re: CPU load about 10% for every core but audio load maxed

Cifer wrote:

[...]
It doesn't matter either way because what energy saver mode does is lower the frequency and potentially throttle the CPU. In that case the CPU load would be higher. My issue is that the CPU load I see is very low while the audio load is maxed out.

(again might not be related...)

I just noticed: there is also 3 options on the "Multicore Rendering" option: Off, On, Max
I never noticed the "Max" before...
with "Max" I can do 256 polyphony in CPU powersave mode using only half the CPU no matter what I do to try overrunning it... (i7-6700T) win!

(hmmm, I'll copy this to the thread I started before...)

Reply by Sanderxpander

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Re: CPU load about 10% for every core but audio load maxed

I'm not really a low level computer architecture guy but there are more components to low latency audio than just the speed of the CPU. For instance the CPU may only need to do a few calculations but the latency between receiving the calculation information and passing it to the audio driver may be too high for the operation to complete within the set audio buffer. This leads to a CPU not maxing out yet still doesn't produce stable audio.

Generally speaking, take all of those meters with a grain of salt. They generally don't measure the total picture and should be taken as a coarse indication of the program load.