The release of NVIDIA's GeForce 375.57 graphics drivers wasn't the most smooth. It introduced a few bugs into the package, which was likely due to all of the games that were coming out at the time. One issue introduced artifacts in animated GIFs, which could introduce seconds worth of black blotches. This was supposed to be fixed in the next WHQL driver, but it slipped. Since the next WHQL driver is looking to be a couple of weeks out, NVIDIA released a hotfix.
The driver also fixes “occasional flicker on high refresh rate monitors”. I'm not sure how old this bug is. I've heard some people complain about it with recent drivers, but Allyn and I have noticed weird snowy flickers for several months now. (Allyn actually took slow motion video of one occurrence back in May.) I guess we'll see if this is the same issue.
You can pick up 375.76 Hotfix from NVIDIA's CustHelp.