Disable vsync and don't play in windowed mode. Use exclusive fullscreen. Force vsync off in the driver to be sure. Don't use ANY command line options. "-novid" and "-freq 144" are the only ones you can use. Don't use any autoexec commands that "tweak" performance. Just fps_max and rates.
If you messed up your game with idiotic console and startup commands, you need to delete everything and let the game create clear new config files. If you don't know how to do that, then I'm sorry. Don't touch things you don't understand.
The views and opinions expressed in my posts are my own and do not necessarily reflect the official policy or position of Blur Busters.