Fooling ReadyBoost
ReadyBoost is intriguing and I’ve been wanting to play with it since I first installed Vista, but my 1 gig USB memory stick tests as too slow, so ReadyBoost refuses to use it.
While reading part 2 of Mark Russinovich’s excellent series on the Vista kernel, I came across his
screenshot of the EMDMgmt registry key, which is where ReadyBoost caches the specifications of your memory device.
There were a few entries in here and I didn’t know which corresponded to which device so I deleted them all, and inserted the memory stick. ReadyBoost again tested it and deemed it too slow. I removed it, and looked in the EMDMgmt key again and presto, there was one entry.
After updating this entry so the values matched those in the screenshot, I reinserted the key, brought up the properties for the USB drive, and it showed ReadyBoost was available!
Now, the theory is that in my case, ReadyBoost will actually make my system slower, since the RAM or the transfer rate for my USB stick is slower than the hard disk – there’s not much point in caching if it takes longer to get the cached data than it does to get it from disk – but that’s not the point. Now I get to play with ReadyBoost.
April 3rd, 2007 at 6:40 pm
Thank you for posting this- not that I want to fool Vista into slowing my machine down, but just because it’s part of a related question I’ve been seeking an answer for.
Does the ReadyBoost test compare the Flash device’s performance against your actual existing hard drive speed? Or does it just benchmark against some arbitrary “standard” value that Microsoft thinks is good?
I ask this because Vista on my machine rejects every USB Flash device I’ve tried: they are all “too slow”. I have a fast drive subsystem (two 10K RPM WD SATA 3 RAPTOR drives in a RAID 0 array) and 4 GB of RAM, so I could imagine a real test of the USB device versus my drives could lead to the “too slow” result. Or it could just be that my USB interface and/or every Flash device I’ve tested really *is* very slow.
Thoughts?
September 3rd, 2007 at 11:50 pm
flash memory is 10x faster than disk