Latency with NVIDIA Prime

Hi,

After using Bumblebee to control the graphics switching on my NVIDIA Optimus laptop (GeForce 540M card), I decided to try Prime as I heard the fps was a lot higher.

And apparently it's true, the fps is a lot higher (going from 45fps to 90fps with a higher resolution ). However, I also seem to be getting a constant latency/input lag on anything I do. For reference, the main game in question is Team Fortress 2 that I'm having a problem with. I have run steam from terminal with

__GL_SYNC_TO_VBLANK=0

as well as putting that same line in my launch options. Curiously, even before I used this line, tuing vsync on or off did nothing (I hear you can't actually use vsync on Prime).

So, my question is, has anyone else experienced a sudden jump in latency/input lag since making the Bumblebee -> Prime switch and if so how'd you fix it?

Thanks for any replies!