Large/ heavy project suddenly glitching horribly - VST instruments don't seem to preload at all?

I have a huge orchestral project with lots of instances of EastWest Play, some addictive drums and HALion and a number of audio tracks. I have a fairly powerful computer (from 202, I7, 32 gb Ram, samples on SSD),

Here’s the thing: this project used to play without glitches or hickups until very recently. Even with video track, even, in fact, if I played a Davinci Resolve video simultaneously.

Here’s what 's happened recently: The whole project glitches horribly whenever I play anything on any VST instrument track, whether EW Play, Halion or Addictive Drums. It seems to “forget” all the notes, so it glitches much less or not at all if I play a note that I have played recently. It seems there is zero preload of anything. Whenever a lot of tracks are playing, however, it struggles whether or not I have record enabled any VST track. But it is MUCH worse when recording.

Audio tracks record without issues. It is only VST instruments.

When not playing, the ASIO guard value is around 40% and the “peak” is fluttering nervously between 50 and 75%. Real time less than 10.

I can’t seem to find any setting that would make this happen or stop.

The mystery is that until very recently, the project was smooth as butter.

Any ideas?

Not sure, if this helps your troubleshooting, but to the best of my understanding, ASIO guard gets disabled for the entire chain of active/record enabled tracks. i.e. not just that track, but also any group or fx track that it feeds and whatever they feed etc.

So if one adds a high latency effect at a highly common part of the audio flow, it can have wide ranging consequences. Or something as innocent as doing some fx routing changes can have significance performance consequences.

And in some cases, disabling a send fx in the fx channel doesn’t seem to change it’s latency impact. I had to disable the send in the individual channel(s).

If you have a midi track record enable then asio guard gets disabled for that track. This can have a huge impact on plays.