nope ...
it's a/ the 60Hz bug of current NT systems
everytimes you start a game which makes a vid_restart your screen goes 60Hz
search in the internet for a application called "Reforce" ... it'll solve the problem
if you don't find it, ask me, I'll send you the 60 kB
if you've got a 72 Hz bug ... read what Hsu said ... HL has default fpx_max to 72
... the next max will be your max frequency of your screen in this resolution