For the past couple of months, I've noticed an FPS drop across all my games. I usually play games like League of Legends and DotA 2 so they aren't really CPU heavy. I thought maybe it could be overheating. This is currently my fan status:
It would be cool if you could provide your specs. Most GPUs doesn't allow temperatures close to 100 Celsius, so your GPU seems to be the thing. A thing you could do is to clean your case and your hardware. Dust can be the reason why your temperatures have been rising so much.