I’ve noticed an odd behavior in Cubase Pro 10.0.20. If I have a non VST track selected, like a marker track, or an audio track, no overload. If I select a VST instrument track - in this case a Halion 6 track which is utilizing multiple outputs, I get instant crunchy VST overload. I select the marker track, back to normal. I’ve recreated this several times, so looks like an issue… Now I admit this song has a ‘lot’ of VST stuff going on - much of it frozen, but still…
That’s the nature of asio guard. It gives you better performance, but it shifts into a different mode for the selected track so you can play that track at low latency. Turning up your audio buffer size can help if you can’t change plugins to reduce the cpu load on that track’s signal path.
Basically with my Cubase 10 ASIO Guard kicks in at a percentage half of processing power (sometimes), turning ASIO Guard Off or LOW will not do that. Seems ASIO Guard is watching more and more carefully. Mostly i turn ASIO Guard Off, and my project runs fine under higher demands.