Problems with graphics on Gmod?

Is anyone else having problems with the graphics on gmod recently? Randomly everything will brighten up and the shader will go wonky. It also happens to me everytime I get a new steam message at the top right of my screen. Was there a new update to Gmod that causes this or is it just my crap video card. Has anyone else been having problems like this, and is there a fix for it?(other than a new video card)
http://steamcommunity.com/sharedfiles/filedetails/?id=503031409

 

This seems like a DX setting.

Try setting your launch option to -dxlevel 90

 

i actually had this problem for the longest time too, for me it turned out Overwolf for TS caused this and once i uninstalled it, everything went back to normal.

 

Looks like it was Overwolf.