I did an upgrade installation of Window 7 build 7068 (x64) over build 7000 that I installed in January on my Macbook (13-inch Late 2006 with an Intel Core2 Duo Mobile Processor T7200, 3GB RAM). Winver gives: 7068.0.amd64fre.winmain.090321-1322

I ran the Windows Experience Index assessment again, and the base score went up from 2.0 (build 7000 64-bit) to 2.8 (build 7068 64-bit).
With build 7000, my Macbook’s low score was because of the 2.0 subscore of the disk data transfer rate of the primary hard disk, a 120 GB Toshiba MK1234GSX. With build 7068, the subscore of disk data transfer rate of the same primary hard disk went up to 4.3.
With build 7000, the Processor and Memory (RAM) subscores were 5.0, while the Graphics and Gaming Graphics subscores were 3.1. With build 7068, the Processor and Memory (RAM) subscores were 4.8, while the Graphics and Gaming Graphics subscore was 3.1. The Desktop Performance for Windows Aero dropped from 3.1 (build 7000) to 2.8 (build 7068).
The main problem I’ve been experiencing with build 7000 is that Windows Explorer will get sluggish or hang after waking from sleep. Trying to switch directories or file copying, even locally, will trigger the problem. Ending the explorer.exe process and restarting the process doesn’t always solve the problem. A reboot does.