Because no one answered this ancient thread. As well with how many completely ignorant people posted replies not bothering to even attempt to show understanding only attempting childish jokes and mindless replies. I will and can confirm you can raid USB 3.0 drives on w8 onward.
The speeds are not "just a bit faster". The 3.0 usb drives add a huge increase, almost adding their own individual drive worth of speed to the raid. 1 usb 3.0 I have reads at 100MB/s according to crystaldisk, 2 was 190, 3 290, 4 380. For 256gb of storage that cost me $40 and reads at 370MB/s (close to as fast as most people Sata 3 SSDs around 500) what is the issue here people? Write speeds are fast enough as well. Faster than platter drives but about half ssd.
I would wager that the onboard usb 3.0 could go all the way to the 5 gigabits max if you had enough ports. At 10USD a 64GB drive I am tempted to try.
The issue with the videos other people posted are that they are on ONE 2.0 port which gets maxed very easily.
Seriously here.
If you have no answer or no knowledge besides showing ignorance, keep quite. I don't care at all I resurrected the thread. This needed to be fixed for future searches.