Stuttering On Playback

Hi. I have an Ardour file with a lot of tracks. When I try to play it back it stutters a lot, beyond the point of usability. When I disable all plugins (safe mode) the stuttering stops. So I’m assuming that the problem is one or more of my plugins.

What do I do from here? How do I determine which plugin is the problem? Any tips or pointers would be appreciated. Thank you!

At first check the"Plugin DSP load" window:

If you don’t find a single misbehaving plugin (or plugins) there, maybe it is time to do some system performance tuning or/and raise buffers/periods of the audio engine.