Had some great advice from here in the past, and you guys are much better at this than me, so thought I'd reach out again. I've put a TL;DR at the bottom.
I'm the author of Midwood Isle and as part of the update I am planning. The mod has always had some issues with lag, so I'm looking for some advice. I think its related to the mod being an ESM.
I created the mod as an ESP in the LE CK, then turned it into an ESM using the ESMify script for xEdit.
Below is what I found when testing the FPS:
I think the reduced fps and lag spikes are due to the mod being an esm. The only reason I can think of is that (to my knowledge) an esp loads everything as persistent, whereas an esm has everything temporary and loads it in as you see it. That should in theory cause it to run faster, (so no idea why its slower) but it could explain the lag whilst exploring (loading the new cells).
Regardless, I have no idea how to prevent this. With the mod being as big as it is, as well as issues like the grass and sky bug which affect esp files, I'd like to have the mod run smoothly as an esm, but I can't think how.
I'd appreciate any advice
TL;DR - Converting Midwood Isle to esm with the ESMify script seems to cause a lower fps and frequent lag spikes when compared to leaving it as an esp. No idea why this is