Hi @angeh,
Last week it was pretty clear to me that after updating my graphics drivers (AMD Radeon Adrenaline software) something broke, so it was relatively easy to pin point what components I've installed or changed in the last couple of days. After reverting to the last known working configuration, the problem was solved. It did require a couple of hours from the moment I identified the problem, till I was able to get my system to behave correctly; it is a shame that drivers with such problems get released.
I would like to note that I've experienced similar mouse stuttering symptoms with other systems (non AMD hardware). While investigating possible root causes I was amazed by the myriad of signatures that people report (and the esoteric "fixes" you'll find). I guess there are plenty of possible causes for such behavior. For example, in my previous gaming rig, using a Bluetooth wireless mouse (Logitech M720) on a WIFI+Bluetooth network adapter (Intel) would cause random mouse stuttering. The problem was very difficult to debug, because it only occurred under specific conditions at random times. So it would be wise to look into other possible causes besides the video card.
All in all, if you had a previous working configuration, I would suggest you revert to that, then try to identify what breaks the configuration. If you believe it is related to a specific hardware device (ex. Graphics card), try uninstalling that specific driver and/or hardware and see if the symptoms still exist. If you happen to have a spare graphics card (or onboard video card), try using that device to isolate the behavior.
Hope that helps you solve the problem you are experiencing.
