CPU load with multi processing on/off

Cubase
1

Hi everyone,

I have been wondering a while now why Cubase on my system (8-core i9 MacBook Pro 16") has a substantial higher CPU load with multi processing support than i.e. Logic or Studio One.

For example: If I open a completely blank project in Cubase 11, the CPU usage of the Cubase process is around 50% (in macOS Activity Monitor - which means 50% of a single core). Overall, this is not much having 8 cores in my machine but nevertheless: The project is completely blank! Logic or Studio One have a CPU usage around 2-3% with an empty project opened.

Now, the strange things happen: 50% CPU load on an empty project only happens if multi processing is turned on in the studio settings (ASIO Guard is off). When I turn multi processing off, the CPU usage of Cubase goes down to 2-3% - the same as Logic and Studio One. Why is that?

The gap even remains if the project has some tracks inside. For example, a project that generates 30% CPU usage with multi processing off leads to nearly 200% CPU usage if multi processing is on. With activated ASIO guard it is even worse.

I have no drop-outs or other problems but on a MacBook the difference in CPU load means a lot in terms of heat and fan noise.

Maybe I am missing something here but hopefully somebody can explain this behavior to me. Why does multi processing or ASIO guard raise the overall CPU usage so much? Logic and Studio One support multi processing, too, but the CPU usage is substantially lower.

Regards,
Stephan

3

It’s taken me years to find this! This is my exact problem. On a MAC and have always struggled with Cubase.

Have just realised today, when I’m playing a project with multi processing in, my CPU usage in activity monitor is 150-200%. With it off, it goes down to 80%. Still actually high for such a basic project which logic and reaper run at 30-40%.

This has always caused me to get stutters and the project becomes unable to play for more than a few seconds.

4

Unfortunately, there has never been a detailed answer from a Cubase tech. I also reported this in a support ticket … with no results.