Just thought I’d throw it out there and comment on my experiences of running Windows 8.1 from a USB Hard Disk. The USB Hard Disk is a WD Elements Basic that supports USB 3.0 (SuperSpeed).
Using GImageX, I deployed a vanilla copy of Windows 8.1 Professional – which was actually a hackish way of doing things since you have to fix up the Windows Boot Manager afterwards – to the drive after a fresh format of the NTFS file system. FAT32 will not work… well, it may but you may suffer FS breakage with permissions and the like.
From there, I rebooted and chose the USB HDD as the CSM boot target, and was greeted with the Windows logo and the spinny dots. Installation went as normal, asking for license key, set up your account, etc. You could also do UEFI boot which will show your OEM’s boot logo but I chose the CSM boot because UEFI can be a pain in the bum.
The reason I did this installation of Windows is because I have my own optimized version of Gentoo Linux installed and I didn’t want to have to mess around getting the two happily talking to each other on local the local hard disks.
Performance wise, the USB3 HDD is enough to keep Windows running smoothly. Windows knows it’s on a USB and while the “Safely Remove Hardware” icon does allow you to eject the HDD… I expect a BSOD would occur, or just a “Device is in-use” error. There’s a bit of extra latency when applications like Unity3D and Visual Studio start up, but overall it’s not bad. As an added bonus, some of my applications seem to load from the internal SSHD faster than a Windows install on the SATA subsystem. Odd.
On the downside, the USB HDD could be prone to failures and also knocks or falls. I am a clumsy sucker some days and have a habit of dropping things (especially cold weather) but I wanted to do this WTG setup for some time, and now that I’ve done so, it’s pretty good. There’s other things like BitLocker Encryption and whatnot, but to be honest, I’m not going to be using the drive for top-secret operations so I didn’t really bother as BitLocker would add additional overhead and increase the whole deploy Windows from image to disk time.