I have the same problem with the low HDD score in the WEI. Was 5.3 in Vista 64 bits and now is only 2.0 with Windows 7-64 bits.

Updated all device drivers one by one however no improvement.

The machine is a Toshiba M300 Laptop with Intel Core2 Duo, T58000, 2.0 GHz

It seems this is a commun problem on Windows 7 64 bits installs.

Any idea how to solve this?