Would "screen tearing" be the proper description for that?
Well kinda, but not exactly. It's short horizontal lines instead of entire sections of the screen showing different frames. Printscreen won't capture those errors, will post an image taken with camera soon.
EDIT: Here's the pic. The problem is most noticable just after going to a loading screen, probably because the framerate gets so low. Those lines seem to be parts of the previous frame (in this case the main menu) so it is kinda similar to screen tearing in that regard.
[attachment stolen by Russian hackers]