I recently noticed i was having a lot of trouble aiming. At first i thought i was having a bad day, but I decided to do some tests. I did a 360 test. I found out the mouse was randomly moving either to much or to little. I then switched the in_mouse to -1, then in_restart and tried it again and did a perfect 360 every time.

Conclusion: If your having sensitivity issues try typing in_mouse -1 and then in_restart, and see if it helps.