Strange artifacting, but only in Garry's Mod.

Hey all. I’ve been working on my comic and during the posing of a scene I hit this strange artifacting.

https://dl.dropboxusercontent.com/u/100708596/2014-07-12_00007.jpg

https://dl.dropboxusercontent.com/u/100708596/2014-07-12_00008.jpg

Now this only happens on Garry’s Mod, because almost directly after this I played ArmA 3 on all high settings with zero problems. My drivers are up to date and this is on a new Graphics Card.
Specs:
Nvidia GeForce GTX 650
CPU: Intel® Core i7 CPU
3 GB RAM

I really hope this is something minor, because I’m quite irritated that I can’t seem to work on my comic. And there’s only 12 models on screen, including my player model. So I doubt it’s just because I’ve spawned too many models.

also, one last thing. I was running MSI Afterburner during this, it showed that my GPU hit a peak of 63 degrees, would the high temp be causing stuff like this?

63 celsius is ok, it looks like some addon might be causing this tough.

Any recommendations as to what type of addon might be doing this? I have atmos installed, and was using it during this scene. Might that cause it?

It doesn’t give me any console errors either, so I’ve no idea where to start.

It could be literally any of them, uninstall recently installed onese or something.

Thank you Robotboy, it was atmos after all. Well, that sucks. Marked as solved.