Cubase 10 not using all cores on 6950x

Cubase 10 is not using all of the cores on my 6950x (10 core). I noticed some of my projects were exhibiting much worse performance with Cubase 10 so I ran DawBench. I’ve attched jpegs of Task Manager while it is playing: Cubase 9.5.41 is using all 20 cores (hyperthreaded). The exact same DawBench project opened in Cubase 10 appears to only use 9 of 20 cores (with a commensurate reduction in performance). I’ve tried numerous tests (including creating a fresh project entirely in 10.0) and it is always the same result. Anyone else seeing this?

Edit: DawBench is run with asio guard OFF. I see now that Cubase 10 uses all 10 cores (20 hyperthreaded) running DawBench when asio guard is ON, but only 9 cores when it is off . Cubase 9.5 uses all 20 cores with asio guard on OR off.


Curious if you did any registry hacks or other system tweaks for C 9.5? Because C10 should actually be performing better. On my 10-core (20 logical/threads) system, it’s definitely better so far. See this thread for more info:

https://www.steinberg.net/forums/viewtopic.php?f=283&t=147175

And I suggest you reach out to Fabio, who has helped me in the past. He’s been on top of the multi-core/thread issue.

Nope. No hacks at all. I’m on Windows 7 64bit though. You?

Additionally, DawBench is run with asio guard OFF. I see now that Cubase 10 uses all 10 cores (20 hyperthreaded) running DawBench when asio guard is ON, but only 9 cores when it is off . Cubase 9.5 uses all 20 cores with asio guard on OR off.

Interesting – I think it would be worth your time to get in touch with Fabio and get his feedback. There has clearly been some serious work done under the hood for high-core CPUs… I am curious myself what Fabio would tell you. Please do post back here or in the other thread (mentioned above) if you get a chance and if you hear back from him. Overall, I’m seeing a good improvement, but perhaps there are cases that need more work. Now is the time to bring it to Steinberg’s attention IMO.

Thank you, just did that.