I tried it and it probably increase about 5 FPS, not bad, but better then last time.
And ya for CS:S, I did all this guy said, well, only the CS:S Tweaks. http://www.fpsbanana.com/tuts/7467
That+GameBooster = 30 FPS (Lots of fire and players), 80-130ish FPS (Just players and a bit of effects)
And sure man, make me a good FPS Boost config, I'll see how much FPS I'd get. Btw, I want the brightness to highest. (1.6)
EDIT: My specs:
1GB RAM
2.66 Ghz Dual-Core Pentium D
NVIDIA 9600 GT GeForce 1GB MEMORY