Hey chaps,

I recently did a reformat of my PC and when I installed Left 4 Dead again I was met with a very annoying problem I never experienced before. My mouse aim is stuttery, as in it makes little micro-jumps rather than moving smoothly. I did not experience this issue before on the same OS (Windows 7 64bit), the same mouse (Logitech G500) and the same hardware (Q9550, GTX 480, 4GB RAM, WD 1TB HDD).

I have messed with my mouse settings, my OS mouse settings, Left 4 Dead's in-game mouse settings including mouse smoothing and even video options like lowering the resolution, running in a window, turning off v-synch and everything else. Nothing has made any difference to the stutter.

It's rather baffling as I am always playing L4D mod campaigns and never had this issue before. Not sure why a reformat would cause it... I haven't installed anything new I was not using before.

Any ideas?

I'm currently downloading L4D2 to see if it does the same thing.

This problem happens to me when I play Team Fortress 2 (same engine as L4D) and I fixed my problem by installing the mouse drivers. If it's a Microsoft mouse then you need to get IntelliPoint (just google it). If it's another company's mouse (Razor, Logitech, etc.) then make sure you have the drivers installed for it.

I would try disabling multi-core rendering in game settings. Also try triple buffering with vsync on in game options. Hope this helps.

I tried updating DirectX but it just told me I was already updated to the newest version. Steam verified the files and said all was well, neither made a change unfortunately.

I'll try multi-core rendering next time.

EDIT - So oddly I read something CymTyr wrote and tried uninstalling my setpoint software and letting Windows download the drivers for my Logitech G500. This fixed the problem completely.

Weird.

I had Setpoint installed before and played L4D... oh well, whatever, don't look gift horses in the mouth and such.

Solution found. Thanks all.

Hey, we should survive together once I get a new computer :D
http://steamcommunity.com/profiles/76561198017060515

I can run TF2 for the most part, if you have that too.

Sorry for the necro bump, but I googled myself and saw I helped resolve your issues - glad you were able to get the game running properly, SV.
-Cym