I currently have an NVR system up and running on Geovisions newest release of v8.3.3.
It's running on an i7 920 (socket 1366) X58 chipset / Win 7 64bit environment.
Everything is operating extremely smooth and fast except for the audio. And its a strange problem!
check out my post on cctv forums here:
http://www.cctvforum.com/viewtopic.php?f=15&t=20991