How does recording/playing differ from stopped CPU usage wise?

[gova]

I've run into a problem using a few cpu heavy plugins neatly split into isolated and record armed/monitored tracks at low buffer sizes (the lower the worse it gets)
When recording/playing the audio is dropping out very frequently and the realtime CPU usage goes to 50-60%.
When the project is stopped it's hovering around 40% and never dropping out.

If I replicate the same set of plugins in my other daw it works fine.

I'm running on a 6700k, win10 x64.

Any help would be appreciated as I'm loosing my mind over this.