I'm on 12.6 on many machines, but none are doing games but multi-threaded audio work. The only defect we've seen is the "blue tint" when dragging an on-screen window above and to the left of the screen-resolution limits (above coordinates 0,0.) But only on Win7-64 vs. ATI 12.6. WinXP flavors handle that move fine.
At first, I thought maybe this was like a radioactive badge - "Warning! Warning! You've moved a window off the edge of the screen!! We're going to plunge into outer space! Off the edge of the Earth! Warning! Warning!"
And my constant response remains, "So-?!! Who the heck are YOU to tell ME where I can move windows to?!!"
Then I was reading the HICCUPS thread and laughing at those responses. Yes, yes, if my machines could talk back to me... well... let's just say I'd probably have fewer machines.
"I married Hubby so HE could talk back to me - don't you guys start!!"
After a pause, then I often comment to the computers, "I like chopping wood, by the way. Very therapeutic. Wanna see me in action?" My computer names are Ballmer. Jobs. Ellison. Things like that. Gates is a quiet computer now, running nicely, almost forgotten as a media server. Almost forgotten.