Ed Bott —My colleague George Ou has an excellent rant on flash drive performance. As he notes, many people are in for a rude shock when they plug in a USB flash drive, Compact Flash card, or SD card and expect it work well with the new ReadyBoost feature in Windows Vista. Many of those flash devices will fail, with a message that reads: "This device does not have the performance characteristics for use in speeding up your system.”
But George gets one detail wrong in his post:
Unfortunately Vista doesn't report the actual raw data for its ReadyBoost test since it only gives you a pass/fail score making it as useless and confusing as the Vista performance index that's based on a scale of 0 to 6.
In broad terms, that's true. When you insert a new flash device and try to use it as a ReadyBoost device, it either passes or it fails. If you try to use a cheapo USB flash drive that some company passed out at a trade show, you won't know from that initial screen why it failed. But the actual numbers are there for all to see, if you know where to look. Carl Siechert, Craig Stinson, and I discovered this fact during our research for Windows Vista Inside Out, and to the best of my knowledge no one has published this information online yet.
I gathered together more than 20 flash devices I've picked up over the past several years and put them to the test. Follow along in the image gallery that accompanies this post and you'll see how you can measure the performance of your own flash devices.