Project Management questions and long edit save times (Waveform 11.1.0)

[chagzuki]

I've been working on an edit which is rather unwieldy, the file size has gotten to around 150mb. There are a lot of tracks, a lot of midi data and a lot of complex synths. Saving the edit was taking a really time, around 2 minutes (!), so I figured I'd try exporting an archive and reopening it as a new project. Having done that, saving this edit takes only a few seconds, but the file size is the same, 150mb. I wonder what's going on behind the scenes that makes the difference between these two scenarios.
In the first situation the edit was around the 100th iteration, and so that project had 100 edits, whereas the archived and reopened edit is a new project with just two edits. Is there some sort of complex interaction between the edits within a project which means that the more edits you have, the longer it takes to save one? I don't see how there would be... but I never paid a great deal of attention to project management in Tracktion in the past.

[spoontechnique]

I'd like to hear about solutions to this. My projects tend to slow down drastically the further along they get. I haven't been able to diagnose exactly what causes it. I've accepted it as the natural state of projects, that they slow down as they age. But I'm probably missing something obvious, like flattening audio clips or consolidating files.

[chagzuki]

I haven't checked if it saves undo states. I'd assumed not, but maybe it's saving a history. Can't check right at this moment.