CS:S? Then yes using a config can increase fps pretty well, here is what I use for every source powered game.
To use this config make sure you create a folder in counterstrikesource/cstrike/cfg called autoexec, make it a notepad file as well and paste this stuff in it.
r_fastzreject 1
mat_disable_bloom 1
mat_specular 0
r_3dsky 0
r_dynamic 0
cl_ejectbrass 0
r_waterforceexpensive 0
r_waterforcereflectentities 1
r_drawdetailprops 0
cl_forcepreload 0
cl_detaildist 200 //Distance at which detail props are no longer visible
cl_detailfade 400 //Distance across which detail props fade in
cl_ejectbrass 0
mat_fastspecular 1
r_cheapwaterend 1
r_cheapwaterstart 1
r_WaterDrawReflection 0 //Enable water reflection
r_WaterDrawRefraction 1 //Enable water refraction
mat_disable_bloom 1
mat_disable_fancy_blending 1
mat_disable_lightwarp 1
mat_mipmaptextures 1
r_drawflecks 0
r_flex 1
mat_specular 1
mat_compressedtextures 1
mat_disable_bloom 1
mat_disable_fancy_blending 1
mat_disable_lightwarp 1
Merry Christmas!