Ok, this is typically what you get in Unreal Engine 4 games with smoothing on and 1000+ Hz. It is completely unrelated to the OS though, and a deliberate (and horrible) function of the game engine. In CSGO with raw input on I have never encountered this though.
Have you tried to check the sensitivity with a tool like Kovaak's sensitivity matcher? Although it does not replicate a physical mouse input, it does usually (but not always) stress the OS and game enough to check for inconsistencies.