Weird computer lag!

[Dalith]

Hello

When playing CS:S I get this weird problem.
Whenever someone's planted the bomb and when I go to defuse it, I lag like hell when I "look" at it. FPS goes from 90 to 20.

Anyone know the solution for this?

Oh and, I have another weird problem.
Like, when I move my mouse it's not "smooth" so to speak. Feels like moving an old wireless mouse that has almost dead batteries. And this isn't cordless but it's USB.

 

[TrippyG]

do u have an optic or ball mouse ?

 

[Dalith]

do u have an optic or ball mouse ?

Optic
12345

 

[THUGENSTEIN]

Maybe the mad graphics of the bomb make your fps worse

 

[Dalith]

I'm playing 800x600 now and this problem haven't happened again.
Something new occured though.

CSS is so dark so I put Gamma to the brightest so I can see the test text, but it always resets everytime I restart CS:S/HL2/HL2DM.

Anyone know how to fix this?
config.cfg isn't read-only.