I've searched up, down, and all around for a solution for this problem (which has been a known one since 2012), but couldn't find a solution anywhere.
I start up the game, all's well and good, FPS is locked at 60, exactly where I want it to be, as to not have every object in a square mile fly off to Sovngarde. Then, the Youtube video playing on my second monitor ends, and I want to go look for a different one. So, I alt+tab, go about my business, and return to the game only to find out the framerate is now unlocked.
First of all, I know I can globally cap framerates in Nvidia Control Panel, which I have done, to 144, since I own a monitor that supports it.
Second, I've tried multiple configurations of the .ini files and NvidiaCP to try to get things working the way I want them, but there's still always that difference before and after alt+tabbing.
If I could just completely turn off Skyrim's frame capping, I can set a cap in NvidiaCP to Adaptive-Halved, effectively capping the framerate at 72 FPS, which would be perfectly acceptable (and does work! ... after alt+tabbing), but before alt+tabbing the game is locked at 30... I know about "iPresentInterval", but this seems to have zero difference on the described issue.
If anyone has found a solution to this, I'd appreciate it a crap-ton if you'd share that solution with me.