At exactly one hour intervals my browser will stall for a few seconds. Sound and video will still play, in fact the browser seems to work but my inputs will have a delay of a few seconds. If I click a link it won't go through or if I type something it won't spell out until a short time has passed.
Also if I have anything outside or have had anything outside the browser open I will be able to see this each time. A "not responding" bar will flash at the top of the browser then two to six seconds later it will flash again. In between those two I will not be able to input anything. It seems to be the same phenomenon but simply more visible.
If I close the browser and reopen it the timing will be reset. It will now happen each hour at the time (or about a minute after) I reopened the browser. So if say I open the browser at 6:40 I will get this stall at 7:40-7:41, 8:40-8:41, 9:40-9:41, etc.
It's not catastrophic it's just a little annoying.