I've been using 3 cameras for about a year (?).   Actual starting date unknown.   Over that time I have been dealing with slower and slower response from all of those cameras.   It is slow when live viewing, and even slower for replay.   The tipping poing point for me was when I wanted to review some activity behind my property.   The replay took at least 5 minutes to start, then advanced roughly one second every minute.  I have tried everything suggested to improve the performance, to no avail.   

I'm only writing this to inform you of the problems I had with those 3 cameras.   As I noted, that was the tipping point.   2 of those cameras have been scrapped and replaced with a different manufacturers product -- they were in areas that are critical for my purposes, and were simply too unreliable.  The last remaining one is primarily being used to notify me of activity, which works as it should.  I won't waste my time trying to review that activity.