With 4 GB SD card, no Vista ReadyBoost:

Direct access speed: 9.95 MB/s; cache enabled access speed: 13.13 MB/s; ratio: 1.3.

With System Memory, no Vista ReadyBoost:

Direct access speed: 9.96 MB/s; cache enabled access speed: 31.979 MB/s; ratio: 3.2.

With 4 GB SD card + System Memory, no Vista ReadyBoost:

Direct access speed: 10.04 MB/s; cache enabled access speed: 11.578 MB/s; ratio: 1.15.

With System Memory + Windows Vista ReadyBoost (4 GB SD card FAT32 formated):

Direct access speed: 16.759 MB/s; cache enabled access speed: 326.279 MB/s; ratio: 19.46.

With System Memory + Windows Vista ReadyBoost (4 GB SD card NTFS formated):

Direct access speed: 16.99 MB/s; cache enabled access speed: 327.65 MB/s; ratio: 19.284.

Windows ReadyDrive of Intel Turbo Memory is working. Windows Vista too, fast and smooth.