Left 4 Dead stuttering issue

[RHICTKY]

I've been having this problem for some time now, anytime I play online the infected will start to jump around and sort of stutter while running. I've captured the problem in the video below as reference:

http://youtu.be/rxa6qOhboGU

My system specs are the following:
-Intel Core i5 750 (Quad core @2.6 GHz)
-Nvidia GeForce 660TI
-8 Gb RAM
-Windows 7 OS

It doesn't seem to be my Antivius, my firewall or even my connection (my ping is a little low in the video but the same issue arises even when I or my friends host the game). Left 4 Dead 1+2 are the only games where i'm having this problem. TF2, UT2k4, CSS, HL2DM all work fine.

I'm asking for any help or thoughts someone may be able give.

[Gustavo Eats His Own Chicken?]

Ya know that happens to me but im on the XBOX version sometimes its just the server.. or the servers location it has happend to me in mvm in tf2..

[Marcus101RR]

This is clearly the server not your end. Notice how your ping spikes drastically. Your fps didn't change, but the zombies stutter their own movement. Move to another server

[RHICTKY]

even though it still happens when I host localy?

[Gustavo Eats His Own Chicken?]

Maybe its your computer??

[PCConsoleGamer]

Try turning off multicore support.

[RHICTKY]

Well thank you for the suggestions but the proplem persists. Looks like I'll just have to resign myself to playing single player.

-edit- Well it turns out that my rate was set to 1000 somehow, turned it to 20000 and now it works fine.

[Pangia]

And where is that stuttering on video?