Hi Fabio,
I also don’t find the solution really satisfying. I’m glad it fixes the problem in terms of making the symptoms disappear, but it’s unsatisfying in the way that I’d prefer to understand why a particular problem is appearing and why a particular action fixes it. That setting the audiopriority to “Boost” gets me rid of the spikes is just a lucky shot that went on target. Btw at the studio of a friend of mine who works with a very similar setup we could provoke the spikes as well. He’s mainly doing audio so he had the priority set to “Boost” from the start and had no spike issues, but when setting it to “normal” for a tryout, he got them as well. I doubt testing it on two computers qualifies my findings as a proper study done to scientific standards, but at least I could verify the connection between audio priority and the CPU spikes on more than one computer.
I agree the problem is poor realtime performance because of other tasks getting in the way. The spikes mostly appeared when having a miditrack set to record mode; to my understanding this deactivates the ASIO guard as MIDI a real time application, right? So the crucial question which I could not find an answer to, is which realtime task is getting in the way of Cubase. As for the settings in Windows and BIOS, I’m sure they’re all what they should be for audio use. Not saying I’m the biggest nerd on those issues, but I’m a professional for more than 20 years, so I think I know my stuff when it comes to that. I considered the Graphic card as suspicious as well and even changed it, but that didn’t improve things.
When running Latency Monitor while having Cubase running, it showed the spikes seemed to be linked to an svchost.exe process. That didn’t make me a hell of a lot smarter, as it’s a system process linked to plenty of tasks, it don’t provide any specific information, also it’s not a process you could just get rid of. Svchost ist also linked to all kinds of automatic updates for instance, and though I disabled all of them (which is quite some effort in Win10 as this OS is a real bitch when it comes to that) it might be that Windows is still trying to do something on the background which it considers more important than what’s going on in Cubase. But that’s just a guess, I didn’t manage to really find out what’s happening there. So in case you know more or the svchost issue gives you a hint in specifying the problem, then I’d love to hear it.
I can live with the solution as it is now, but I consider it a medication that eliminates the symptoms so they don’t bother me anymore. But I’m sure it’s not a cure to the actual disease.
However, I blamed the problem rather on Win10 than on Cubase 8.5, but I notice some people seem to have the same issues on a Mac, so it might be a Cubase issue after all. I’m not losing sleep over it anymore as I can work on the system now, but still I’m curious to rationally understand what is happening there and why it happens.