Played an official the other day using libra and whenever a screenshot was taken I would get a 3-5 second period in which my screen would completely freeze an after I would experience jittery game play for a while.

-windows 7 x64
-intel 9940 quod core@ 2.66ghz
-8gb DDR3 corsair
-ati radeon hd5770

task manager.

Set CSS/HL2.exe to High priority

Set Libra to low Priority

Try that in a public server see how it goes. Then repost if problem persists.

//Switch