Just upgraded a bootcamp partition from XP Pro 32-bit to a Windows 7 64 bit clean install without any significant problem on my 2006 Mac Pro. The bootcamp partition was on a hard drive also containing a normal Mac partition. The onyly preparation that I did was make a copy of the Windows 7 Pro Update install disk via instructions found at: http://jowie.com/blog/post/2008/02/...t-from-Vista-x64-DVD-burnt-from-iso-file.aspx The ONLY issue was when the install program reboots during installation after booting from the DVD, I had to hold the "option" button on the keyboard to make sure it rebooted to the hard drive, rather than the DVD as it did the first time. My startup time is about a minute. Windows recognized all 12 GB of memory. Runs REALLY well - better then Vista Ultimate I briefly installed when it first came out (Bill Gates Signature Edition no less!). Sound is finally is coming out of the Line Out jack - which I could never get XP to do. The volume is low, as others have reported. I just turn my speakers up - just turn them back down when I go back to Mac. I am going to install the latest RealTek audio drivers next: http://www.realtek.com.tw/DOWNLOADS...=24&Level=4&Conn=3&DownTypeID=3&GetDown=false I am using a Logitech Edge bluetooth keyboard via a small bluetooth dongle without any problem. I have a NVidia 8800 GT and Windows had no problem finding a driver for it. My dual 30" monitors work perfectly. I am running a 64-bit version of Windows 7 on my "ancient" 2006 Mac Pro. It is very frustrating that Apple cannot be bothered to create a workaround so I can use Snow Leopard in 64-bit mode. I do intensive medical imaging-related work, as well as video and audio pro apps. Breaking the 4 GB per app barrier would be very helpful. It is ridiculous that Snow Leopard cannot take FULL advantage of my 64-bit computer (advertised as such) but Windows can! Of course I will use my Mac for most everything, but at lease now I can tap into all of the raw power my computer has, despite Apple's pathetic abandonment of my 2006 Mac Pro.