Totally the opposite of my experience on MC 6 running on a self-built Windows 7 PC.
Fast, stable, AMA works well, although for quickest editing you will want to transcode to DnXHD.
Avid's #1 media management is something Adobe could learn a thing or to about.
I edit Red 4k, P2, XDCam, and DSLR footage all day on it and it works well.
McGee Digital Media Inc.
24P HD Production and Post
http://www.mcgeedigitalmedia.com