I too have a problem with FPS. The game drops to levels I consider unplayable.
Here's what I posted in the main thread, no reply as yet...
Have to say thanks to Monty and co., however CUP suffers the same issue for me as TFM412. I tried going back to 4.10 with DBW+TFM and that also has the same issue.
And that issue is framerate.
As an example I run the P40B Pearl defence single mission - on the ground just idling before take off I'm getting no more than 50fps, when I'm in the air I get no more than 60 fps over the mountains and hills of Oahu, and when I get over Pearl that drops to about 30 fps and occasionally down to the late 20's with all the AI aircraft around.
Another example is sitting on the deck of a carrier with a full flight, I'm getting at max 40-50fps, and when the AI start up that drops to 20-30fps.
In comparison if I run just the TFM412 map packs, the TFM412 RAF01 and RAF02 packs, Carsmasters HD textures mod, the basic SAS modact addons (FOV mod, missionpro, visualmod, random belt start pos etc.), and the TFM42 XX packs (radio, sounds, menu etc.) I get about double the framerate I get when running TFM412 or this CUP pack.
So what in CUP (and TFM412) cuts my framerate by as much as, or more than, half? Is it the (number of) static objects on the ground? Can they be easily removed to improve framerate?
BTW my rig specs (the relevant bits) are - AMD Phenom II X4 955 @3.2ghz, Gigabyte Geforce 960 GTX (mini ITX version), 8GB 1333mhz RAM, 7200RPM HDD, Windows 7 64 bit.
If it's a simple matter of going back to stock 4.12.2 effects that'd be great, but I doubt it's just effects related, not for me at least.
A real shame as things do look great with CUP (and previously TFM) installed.