Come to think of it, on my old rig I disabled actors with torches and any plugins that added fish. Those two decisions bought me back some fps.
I can attest to that statement... I removed mods that added fish as well. I also didn't install NPC's with lanterns or Castle Wall Defenses for MMM.
Haven't gone as far as removing NPC's with torches though, but I can see how that would really improve nighttime performance
within cities.
My rig isn't top of the line, but is pretty snappy. Even I hit some extreme lows in FPS, but usually only when I have more than 5 NPC's on screen in a world cell. Or when I fight a hoard of creatures. (5 or more)
The lowest FPS I've hit is 15. This usually is only seen at highly populated world cells like Anvil Docks, IC Waterfront and Bravil Docks all with Better Cities enabled.
These spots are also where I experience immersion killing stutter when these cells initially load.
I run all the standard heavy mods... RAEVWD, QTP3R Further Reduced, Better Cities (sometimes Open Cities) , FCOM, XEO5, All UL mods, All Natural, AWLS (disabled chimneys) OGE w/ GodRays,SSAOv2 and Edge Detection Shader with EdgeAA enabled.
I also use OSR with heapmode enabled. (Experimenting between algorithm 1 and 5) Streamline 3.1 (Only using Streamsight with fog settings set for "12")
I've Pyffid all my meshes for all mods and have also created .BSA files for all large mods. I also use Operation Optimization, Polygone Reducer (Polys B Gone)
and Optimized LOD Max, Those last three mods improved my FPS by about 3-5 FPS. Also reduced stutter. Pyffi and OSR probably provided the most dramatic
improvements. My FPS didn't increase, but my stutter reduced tremendously from those two mods.
OCing can definitely contribute to an unstable game. Last night I found that my video card OC was causing my CTD's.
Funny thing is, I didn't have any CTD's up until I added Better Cities and UL mods. Which leads me to believe that my video cards VRAM was getting overly stressed.
Once I put my clocks back to stock, the game was way more stable. I still CTD'd but my game session lasted WAY longer. My CPU OC seems stable though.
I limit my game to 30fps in order to leave more CPU power to process A.I. as well as allow for a smoother gaming experience. (Game isn't fluctuating on FPS but rather focused in on a target FPS. This is done with OSR.
I install and load the game from it's own solid state drive. Increased load times 10 fold and also improved stuttering caused by harddrive trashing when the game is searching for files to load. I run at 1280x960 @120hz resolution for 3D Vision on an old CRT monitor with 16x AF and 16x AA. However, OGE disables AA so not sure if there is still performance impact from AA. I have all in games settings maxed except I lower trees, actors, objects and items down to 75%. This frees up about 3 FPS and further reduces stutter. I hardly notice the change since I am using 150% larger Vegetation and 1.5x larger distant trees mods. I also turn off self shadows, interior shadows, exterior shadows and window reflections. i find Oblivion shadows ugly and with SSAO, I don't see a real need for them.
Hope some of this helps.