Bug/Issue Lag since update

I've been having huge issues with the game lagging since the recent update– it seems to slow almost to a stop when I am around lots of monsters or NPCs, swinging my sword at a monster, at my home base, or around weather/particle effects, it seems.

Everything was working fine before the update (and, strangely enough, for a short while after). I've tried removing all of my mods, playing with a new character, disabling vsync, disabling the steam overlay, opening the game directly (not through steam), installing fps boosting mods, and uninstalling/reinstalling the game, all to no avail.

I can't think of anything else to do but the lag is making the game unplayable! Any solutions would really be appreciated. Here are my specs:
MacBook Pro (Retina, 15-inch, Late 2013)
Running OS X Yosemite 10.10.5

Processor: 2 GHz Intel Core i7
Memory: 8 GB 1600 MHz DDR3
Graphics: Intel Iris Pro 1536 MB

 

My zoom level is at 2x, sorry I'm not great at getting the other stuff precisely but here are some screenshots from activity monitor that will help hopefully. It's maybe worth noting that the computer gets like... scorching hot when I play. I have a fan control app going but you could still cook on the surface of it. (Note: the steam % CPU jumps around from 1% to 20%, it's pretty inconsistent)