I downloaded the new Windows 7 Beta (64-bit) and did a clean installation on my 3GB MacBook (13-inch Late 2006 with an Intel Core2 Duo Mobile Processor T7200). I used the Apple BootCamp64.msi drivers and all the Apple hardware devices installed correctly.
In November, I tried the 32-bit version of Windows 7 (build 6801) and the Windows 7 Beta (build 7000) doesn’t seem too much different.
When I ran the Windows Experience Index assessment, the base score was 2.0 (build 7000 64-bit) compared to a base score of 3.0 with the 32 bit version of build 6801. The low score was because of the 2.0 subscore of the data transfer rate of the primary hard disk, a 120 GB Toshiba MK1234GSX. But I don’t feel there is any sluggishness while using the computer.
The Processor and Memory (RAM) subscores were 5.0, while the Graphics and Gaming Graphics subscores were 3.1, not unreasonable for the Intel GMA 950 graphics processor. Anyway, I don’t have much ambition to play Crysis on my Macbook.