problem with fps

[kubaz3]

Hi, so i have i problem when i format my pc i will get solid 300 fps in cs go for example. After coule of days it will drop to 200 and drop down to 90 sometimes. I did changr my gpu same thing dont know what to do. And csgo is not the only game.
My specs
Motherboard: MSI Z87-G43 Gaming Series Intel Z87 (Socket 1150) DDR3 ATX Motherboard
Motherboard BIOS: v10.2
CPU: Intel Core i7-4770K,3,500 MHz, turbo3,900 MHz
Memory: 16GB Kingston DDR3
PSU: SuperFlower Golden Green HX 750W "80 Plus Gold" Power Supply
Graphics: Gigabyte GeForce GTX 770 WindForce 3x OC 2048MB GDDR5 PCI-Express Graphics Card (GV-N770OC-2GD)
Graphics Driver: 347.25
Operating system: Windows 8.1

 

[Danny75]

What drive are you using?

Could it be that GeForce Experience is automatically optimizing the game a day or so after you format, and increasing graphics quality therefore less FPS? Or do you optimize right after format?