What is your processor? RAM ?
Sounds your CPU is overheating. Maybe you should clean your computer ( Cooler, CPU ). Remove dust...and if check whether your CPU fan is working or not. Anyway, when your FPS drop to 10-20. Right click on task bar and open task manager. Go to Performance tab. If your CPU performance bar is more than 90%. Your CPU is heating. Therefore, you gotta clean your PC / Install a good CPU fan / cooler.
Close unnecessary programs that can have a big impact on your in-game lag. ( Torrents, Music Streaming, Internet Browsers and other downloaders )
Scan your computer for malware
Uninstall ENBs and other mods affect your in-game FPS.
By the way, that mod is not allowed I think,
woot wrote:Usage of any mods (whether cleo, asi, or anything else) that increases your FPS cap above the default 100 is strictly forbidden because it modifies the game engine in a way which gives you many unfair advantages.
You are allowed to use crashes.asi, however you must turn your FPS limiter on in settings.
Anybody found having more than 100 fps will be warned, on the second offense a ban will be issued.
Admins can see your current FPS anytime.