Wow! This is a big bug – and was suffering from it! As soon as I got the first beta of Vista that included ReadyBoost I went and bought a 1GB flash stick and turned ReadyBoost on.
Vista has always started slow for me – even from a hard boot. But my hard drive was also almost always on – my drives were being thrashed like crazy.
After reading this I shut off ReadyBoost and removed the USB flash drive.
The difference? Now it takes about 50% less time to start after a hard reset, and about 70% less time to start after a wake of from sleep.
If you are using ReadyBoost shut it off, and see if things are any faster at startup.
Robert Hensing, a security engineer at Microsoft, wrote on his blog about a performance flaw in ReadyBoost which severely hindered the responsiveness after resuming from standby (S3) or hibernate (S4) due to an architectural bug. The problem causes irregular and unnecessary hard-disk thrashing after resume which can take up to 8 minutes to settle down – ironically the outcome is the exact opposite of ReadyBoosts purpose to increase responsiveness by caching. The cause is a simple yet stupid oversight in the design of ReadyBoosts security system which encrypts all cache-data with an AES-128 encryption key, a great idea badly implemented.