I'm getting this exact same issue. I can't watch any premium streams due to the constant buffering and stuttering. I have a 40Mbps connection and never have an issue watching any other streaming video except the ones on Giant Bomb. I can always fall back to youtube for the free stuff but the stuff I'm actually paying for (Subscriber content) is completely unwatchable. I just tried to watch the Evolve trailer and it couldn't even make it more than 30 seconds in to a 2 minute video without constant buffering. This happens on all video quality settings.
I'm running Chrome 32 in Windows 8.