Fallout New Vegas Framerate problem

[Pocketguns2]

I've been having some framerate issues, but it's not like random. I have the portable tent mod and i get around 50fps in there and a reasonable amount outside, however after playing for a few hours my framerate gradually decreases, now in the tent mod i get 15fps, I'm like really confused as to why it's doing this. It's when i normally get to around Novac but i notice it before at the Mojave Outpost and Nipton. I am really stumped and any help would be appreciated!

 

[HEXiT]

if its a gradual slowdown that doesnt recover then its likely theres a memory leak. run a mem cleaner/optimizer/recovery app in the background and enable it every 20 mins or so to see if it helps.