I’m having same issue with 10.5 as I had with 10.0.5 that made me go back to 10.0.4. Cubase is spiking with nothing much really going on in the session.
What changed from 10.0.4 to 10.0.5?
I’m on 2009 Mac Pro high Sierra 48 gigs of ram. 8 core.
Seems like 10.04 is last version usable for me.
Seems like it isn’t just Windows 10 then since I have that and you are running OSX. Something in 10.0.5 appears to be broken and it has carried to 10.5. Take a look at your actual CPU usage outside of Cubase. The same project running on 10.0.3 almost doubles actual CPU usage in 10.0.5.
In my case I had a large template and it had many instances of slate vcc plug in it. Which was never a problem. What someone suggested was to remove and reinstate those plugs on the tracks. I did that with all the plugins in session. That fixed the issue.
I’m having severe CPU spikes on 10.5 while 10.0.5 runs very smoothly for me (running the exact same project with under 10 tracks and nothing fancy in it) so for now I can’t work on 10.5 - tested with Focusrite 616, Presonus Quantum 2 and just bar Asio4all driver.
On 10.5 it seems to be that Asio4all performs better against Focusrite and Presonus. Running Windows 10 with the latest updates.
I fixed the problem by removing all the plugins and re adding them.
I can confirm that removing all slate VMR instances from a project / template and reloading them fixes the issue. Deal breaker for anyone in the middle of mixes at the moment! Going to report this over at Slate if anyone would like to join me. . .