Because my MacBook Air has only 128GB of storage on the SSD, I'm trying to run Parallels off of a PNY 128GB USB 3.0 flash drive. It's essentially hopeless...it takes a VERY long time to boot into Windows, and once Windows has been booted successfully, it can take several minutes to open an app. What I don't understand is that in running BlackMagic Speed Test on the SSD vs the flash drive, the flash drive read speed is about 50% of the SSD, and the write speed is about 25% of the SSD. So, I'd expect things to take, at most, about 4 times as long off of the flash drive in comparison with the SSD. Has anyone had better success with this than I? Another option would be to create a small external 3.0 SSD drive by taking a 2.5" slim enclosure and putting an SSD inside. Is that likely to be faster? Thanks for the help.