I won't be home until tomorrow to test new stuff but here's all the troubleshooting I did before I posted my original message:
I tried running the game with fps limit set to 36 and 60 for each of the RenderAheadLimit values I mentioned earlier. Even with 36 the framerate always dropped to 3-5 fps eventually. Setting graphics to low with AA and such off had no effect either.
I've run NewUIs TDC for a long time now, currently have an almost up-to-date version (seems TDW released a new version this week). I've had a wide range of mods installed i.e. environment mods (currently running Dynamic Environment), sound mods, IRAI and all those little fancy mods that add realism and immersion to the game. And none of them have effected performance in any noticable way except MO.
I even loaded the game with MO as the only mod and the problem persists, so it's not a issue of incompatibility between mods either.
Tomorrow I'll try setting the RenderAheadLimit to 3 and also test the light shadows mod. This gets me thinking, does MO use some (heavier) shadow mod by default? I don't think the mods I've used change shadowing so I've probably only run vanilla shadows to date. Are there any other mods included in MO that have an effect on rendering so maybe it/they could be disabled? This is a bit baffling to me since the game indeed has an awesome framerate with max settings on my rig with any other mod except MO.
Thank you all for the tips, hopefully I get this solved tomorrow.
