I run the pimp distro since a couple of hours.
Also on AsRock H81 BTC and nothing changed, still dropping.
Did you try the xorg.conf that I posted the message before yours to see if it helps with the rate dropping?
I do since 15 minutes and so far no drop!
Is there a screensaver starting on X?
The screen does black out after a few mins. Another interesting thing about my other rig that didn't drop at all is that I unplugged the monitor cable from the GPU so I could use it on my Asrock H81 board that do need a monitor plugged in to start. Don't know if that has anything to with it, but... let me do some test about that monitor being powered off by X scenario....