2 posts ago, i showed you why having MySQL data on a flash thumb drive no matter how fast will not give you good database performance, But what about Windows ReadyBoost
I have already tested ReadyBoost to validate my theory before presenting it here, The answer is that ReadyBoost will NOT help with MySQL DBs, The reason is that ReadyBoost probes for file size and will only work on small files, large files such as your MySQL MYI or MYD files are skipped automatically.
How you can know this is correct, or how i probed to check that ReadyBoost will not work, i installed the flash drive on a Windows7 Machine, a good SANDISK 16GB extreme, i set it up for ready boost, and i watched the Blue Light that blinks when there is reading or writing, from the minute i executed the script that should talk to MySQL to the end of that execution and the ones that came after it, the blue LED did not blink, and so i know for fact it does not work with MySQL.
An exception would be if you had very very little data (The MySQL data files are very small), but in that case MySQL would have them cached in advance, so there would probably be very little to gain
I think web servers could make use of readyboos for those photos and similar small files, but then again this is just a theory.