MSF and Cubase 10 cpu problem

[dionenoid]

Here's a weird one :

When i'm using MSF in Cubase 10 and switch on "Constrain Delay Compensation" in Cubase (always do that when i want to play something), the cpu useage goes to extremes and causes Cubase to hang.

When i switch "Constrain Delay Compensation" off, the same thing happens again.

After some searching i found that MSF was causing this, even when it's bypassed.
When i take MSF out of my project i have no problems. Put MSF back in and the problem is back.

This extreme cpu useage also happens when i switch other plug-ins to different upsampling modes or advanced settings that change latency of these plug-ins.
Normally i can do this without any problems but when MSF is in use in the project it causes serious problems.

Btw : in all these cases both cpu and memory useage goes thru the roof. It doesn't crash Cubase, but makes it hang for several seconds or longer, depending on what's going on in a project.
When i then just select the track that MSF is on, the cpu meter goes down and i can use Cubase again. Very weird.

I'm hoping there's a setting in MSF that i'm overlooking. I didn't notice this problem with the previous version of MSF tho.

(I'm on the latest version of both Cubase 10 and MSF, on Windows 7 64bit and RME Fireface UFX)

[MeldaProduction]

Hmmm, well, I just tried, no problems. Please try to make some microscopic project with a single instance, that would do that and send it to me to info@meldaproduction.com.

[dionenoid]

Did you also try in a busy project containing also other brands of plug-ins and/or external plug-ins ? Because in a simple test project i don't have this problem (already tried that). It's only in my actual production projects when it happens, projects that already use 40 -50% cpu, external fx and also UAD plug-ins...

I will try some more, see if i can pinpoint maybe a single fx or something else in MSF that starts it, or some settings in Cubase.

[MeldaProduction]

Not really, but I was using CDC regularly when recording and never found a problem really. I have a tendency to blame UAD, due to the transmission latency, especially if you reach that much CPU. Who knows... If you find anything interesting, please let me know. In any case, the plugins don't do anything different when CDC is enable, in fact they don't even know about it. But it's possible that Cubase needs to somehow disable lots of plugins (especially the UAD ones), so it's hard to say what happens at that moment.

[dionenoid]

After some testing i suspect the problem is the Harmony function in MSF. The extreme cpu spikes with CDC seem to only happen with sounds that use the Harmony engine.

(btw : individual volume and panning for the voices in the Harmony engine would be nice).

When i don't use the Harmony engine, i still get spikes (when switching plug-ins or bypassing plug-ins that have latency) in projects where MSF is active. But these are not so bad (usually a second or so). Just weird that these spikes happen, never seen this before.

UAD doesn't seem to have a part in this, i took out all UAD plug-ins and the problem is still there. But i use a lot of plug-ins from all kinds of brands so could be a combination of certain plug-ins that have an effect on this.

[MeldaProduction]

Well, MSF needs to initialize the voice when you press a key, and if you use Harmony function, then you may well be pressing 7 keys at the same time, but it usually isn't that bad unless your latency is very low.