WHAT THE LAG!

Ok I recently Have been Working on a FPS Game. There is a problem tho.
I lag, People Who Play The Game lag it is NOT my computer.

Comp Specs:
FX-8350
32GB DDR3
500GB SSD
3x GTX 780

GAME INFO:
Draw Calls: 1155
Tris: 2.1M
Verts: 1M
Used Textures: 20
Render Textures: 2
VRAM usage: 17.3MB to 137.4MB (of 2.95GB)
Shadow Casters: 0
Visavle Skinned Meshes: 2
Animations 5

(Only 3 GUI calls)

I average 40FPS
people who i have testing average like 2FPS
game is written in mainly C#

Can you open the Profiler window and see what is taking the most CPU time? most likely it’s a behavior that is taking too long keeping in mind that a behavior will execute every frame?