I forgot to add several other items.
I frequently use to or three external monitors, the same as I did with my 2007 MBP 15". Sometimes the external display will jitter sideways rapidly.
I play the Zuma's Revenge game at breaks. This is one of those shoot the balls games, and not very demanding graphically. Frequently, it will freeze temporarily, or stutter, or blink off to black, then come back.
I wonder if the hi res graphics chip(s) are failing.
Well, you will never guess what the problem was. I finally took the computer to the Apple Genius Bar in Raleigh, and Katie quickly found the problem. I had been running in "root" off the main HD, not under a "user". Apparently, the machine refreshes everything on the root drive each time a screen refresh is initiated. I had 32GB of stuff on my desktop (root drive).
Katie moved all that stuff to my user directory and voila, everything ran much faster, with no hangs or crashes (so far X). She said don't store anything on the desktop, just temp items.
I don't fully understand what this means. I have always been the only user, so I never bothered with "users" and don't know what the computer does underneath.
If anyone has a clearer explanation, please tell me.
Well, I do know and have mentioned in other benchmarking or performance threads, that having too many objects on the desktop has a clear impact on startup performance, but would never have guessed it got this bad year round. At startup, had observed the Finder busy refreshing and redrawing all the icons (which in this graphics-happy world implied opening each file to create a mini screenshot of the content), and this would bog the process down more and more as you left more items there. But would never have guessed that the Finder's obsession with up-to-date icons would go that far.
Maybe one or some of the files placed on the desktop would require the help of an overly resource hungry app to redraw its icon, maybe even requiring an Internet excursion to gather further info. All this, of course, behind your back while you impatiently wait for the process to conclude. And your observation that the graphics infrastructure seemed to be involved would be congruent, since this is all the OS' efforts to provide better eye candy.
BTW, you may be interested in downloading and running the gfxCardStatus utility. It places a discreet letter in the right of the menu bar, that indicates whether the Intel (integrated) or the Radeon (discrete) GPU is in use, which has an impact on graphics performance and battery life. Also lets you force the use of one or the other, should auto switching prove insatisfactory at a given instant.