I have figured out a way to use flash drives for Vista's Readyboost that would ordinarily fail Vista's fairly strict performance requirements for flash drives it is willing to use for Readyboost. Ed Bott has many details on how Vista tests for this performance. A database of flash drives and their suitability for Readyboost is being compiled by Grant Gibson.

I looked in Grant's database and Pricegrabber to find what I thought was the cheapest 4GB flash drive that would support Readyboost: The Kingston DataTraveler DTI 4GB, which I picked up for about $36 shipped. Only potential problem was that I noticed that there were conflicting reports of its suitability for Readyboost. As it was about $20 cheaper than a 4GB flash drive that worked consistently with Readyboost, I thought I would give it a shot.

The drive arrived today and consistently failed the read speed test, its write speed was about 1700KB/sec. So I formatted the flash drive with NTFS and then right clicked in the drive in Explorer, chose Properties, the General Tab and selected the Compress this Drive to Save Space checkbox. The reported write speed went through the roof to 141320KB/sec. and the read speed was a respectable 4764KB/sec.

Presumably the Readyboost test is writing a string of the same data that gets compressed to just a few bytes by the NTFS compression algorithm, which the Readyboost test interprets as a super fast write. I wouldn't think that the read speed would be similarly affected by this algorithm.

So the net result is that I get to use Readyboost on what would otherwise be a card that falls just shy of Readyboost's required specs.

I haven't done performance testing to see if Readyboost is really helping me that much under these circumstances, although I suspect, but don't know, it is helping me almost as much as a card that had a little faster write speed. I'll leave that sort of rigorous testing to others.