Playback stopping/lagging in Cubase 10.5 project (CPU only at 25% use!)

I wonder if anyone has an idea why this is. The project I’m in keeps lagging and stopping on playback. I was under the impression that this is the CPU being overloaded, but I have a monster 12 core CPU and 32 GB Ram. The CPU use is max 30% and RAM 35% according to task manager.

I just can’t see it being my hardware, it has handled the amount I have loaded into the project without issue before. Does anyone have an idea why this could keep happening? Thank you

That’s not really much info to get an impression of the problem, a video would be awesome to hear the nature of the “lag” and “stopping” and to see how the UI behaves. Hovever, my first thought is:
Have you tried increasing the buffer size in your ASIO driver? Some plugins are not doing well with super low latency and need a larger buffer to work with, things like reverbs and mastering plugins like Ozone.

*On that note, depending on the ASIO driver you are using, maybe try a different one. ASIO4ALL usually works great, make sure you have the latest, stable version of that.

The only other bottleneck I could imagine for now is data transfer from the disk / SSD.

Also, make sure you close any application in the background that is not neccessary and that there is no Windows Update or Windows Defender / Anti Virus scan running that might keep the system busy.

Aside from that, maybe it is one specific problematic VST plugin. Disable them one by one to check if a plugin is causing the issues. Maybe you need to update some plugins to their latest version.