I tried to search but maybe I'm not using the right terms
This problem has been going on for a long time, I guess since I got my 560 superclocked? I don't remember the 5770 having any problems like this. Sometimes when I'm playing a video through Media Player Home Theater 64-bit, XBMC, or KMPlayer, or VLC (currently don't have kmplayer/vlc installed but thinking of reinstalling kmplayer) the video will flicker and flash. It will do so randomly, not at any distinguishable set intervals. Sometimes the problem just seems to not show up, sometimes it does, and sometimes it's really bad.
There is no problem ever when watching videos in full screen from the internet on my primary monitor, except for youtube videos where fullscreen is just not even usable the flickering and flashing is just too bad. I just set youtube videos in large mode and zoom in so it fits most the screen.
I have tried vsync on and off, I've updated my graphics drivers with clean installs, I don't really have anything running in the background aside from microsoft security essentials and malwarebytes. The only codec pack I have installed is CCC. My computer isn't overheating, its well ventilated, it's temperatures for the cpu and graphics card are well within acceptable range even under full load.
Windows 7 Ultimate 64-bit
Asus P5N-EM hdmi
Q6600 @ stock speed, always has been
Evga 560 superclocked @ stock speed (well, stock superclocked speed)
3gb of memory, not sure the speed but pretty sure it's the highest my mobo can handle
500gb hard drive of some kind, 7200rpm
40" Seiki 1080p 60hz tv running at 1920x1080, hooked up via the vga (It's a samsung panel, like most seiki models)
15" sony vaio 4:3 lcd screen hooked up via dvi (my awesome 22" viewsonic screen died,
had this old thing lying around)
I typically play videos on the 15" screen while I'm doing things on the main screen, but regardless of which monitor the video is on it exhibits the same kinds of problems. I guess it may be more prevalent on the 40" I used to play videos while gaming when I had the Radeon 5770, but my 560 doesn't let me do that, the second monitor just stays black. It sometimes lets me if I use regular windows media player.
-I can hook up my 40" with HDMI but the screen doesn't fit no matter what I try and there isn't an overscan/underscan option in the tv menu to turn on or off. I can sort of get it to fit using windows custom resolution thing but I can't move the position of the screen and get full use of it, there is ~20 pixel width space on the right that isn't used on my best attempt at fitting.
---side track note---
Why is XBMC so difficult to use? It's fine for finding videos to stream, but trying to make a playlist or use files from your computer is insanely difficult. I can only get it to play straight through a folder and it stops when it reaches the last file. I can't figure out how to get it to shuffle and I can't figure out how to get a single thing added to a playlist. I am not about to "tag" all my video files to do this either, if that has to be done I'll just not do it and stay with the other media players.