I wanted to run El Capitan on an external flash drive economically to see if I wanted to do a clean install of it on my mac. I am amazed how well this flash drive works. Just pop it in the USB and restart with the option key and off you go. Surely not as fast as my hard drive on the Mac but I have tested the read and write speeds and they are as good as advertised. If I enter to much data at once and or use 2 or 3 programs at once it is a bit slow but it never freezes on me. Just give it a moment and it will sort it out: it has yet to crash. I am also using the same unit P20 jump drive in the 32 GB size for transferring files into El Capitan on the 64 GB flash drive and the speeds are just as fast. I am really impressed that I can this kind of performance for a very economical price. I dumped my whole mail play list file in what seemed like seconds into el capitan without a hitch. I have also transferred whole iphoto into photo as well as downloads and documents.
Now if I can figure how to transfer whole Safari playlist then I will be happy.
This is the fastest USB drive I have used. The case is very sturdy but is a little bit wide. I sometimes have problems when ports are close together. I have 3 of these and have had no problems yet. The 64Gb is the same speed as the 128Gb model... F A S T......