1. ) I found this great program (that has it's own thread on the forums)
And in the settings editor, under the console tab, if you uncheck 'DX deferred CS path' you'll get a great FPS boost. I noticed no visual differences either. I got a 10fps boost on all high settings, this was the biggest fps boost.
BUT I WASN'T SATISFIED WITH JUST THAT! It gave me a good fps boost, but I still couldn't play 64 player servers that well.
2 .) putting these two console commands into the 'user.cfg' (or just entering them in the console may work) will also significantly g ive you a steady fps boost.
3.) I run gamebooster (As many of you probably do) and even check further things that are unnecessary (default settings do not always get them all)
4.) I run windows 7 theme in the "Windows High Contrast/ or classic mode" I pick high contrast cause I don't like the brightness of the classic mode. THIS REALLY helped me at first, and now my computer just runs faster in general, and still looks cool doing so :)
5.) The settings editor for #1 is really helpful.It will allow you to edit settings before you go in game, and also has some useful tabs not put into game.
You could try disabling dx11 effects (though I have read that will have a negative impact, I cannot attest to this as I have not tested it out)
changing the shadowmap resolution is also helpful. I recommend the higher resolution, the lower (I run at 1920x1080, and I put shadowmap resolution at 512)
Tripple buffering I think is enabled by default, but you could also enable that to help.
For me I was having to lower settings constantly on both 32 and 64 player servers, now I can play at high settings. Only down side is very mild blocky shadows.