For those of you who wish to go with a thunderbolt storage solution using windows (I am currently using version 8.1), Promise Technology, Inc. now offers windows drivers for their Pegasus and Pegasus2 line of raid storage boxes. The R4 (4 bay diskless version) can be purchased at the Apple store which as far as I know is the only place that sells it. Due to the high cost of their versions with disks, I decided to go the diskless route and populate the bays myself with four HGST 4TB Deskstar NAS drives. With raid 5 I end up with 10.91 TB of storage. The unit automatically powers on and off with my pc and will shut the disks down if not being used, automatically powering them back up when an read/write request is made. The admin software advises of any issues and I have found it quite easy to use. The unit is temporarily on my desktop and I can hear the fan, but my hearing isn't what it should be. I can also hear my pc fan, so I don't find the Pegasus2 fan annoying at all. When working the drives can be heard.
A word of caution - I read somewhere that Promise won't support a unit populated with drives that are not on their approved list. Their list is quite short and at last look only includes one 4 TB drive which is a Seagate desktop version (actually I own a couple of these drives which I have been using for backups). I decided to go with the HGST NAS drives due to their perceived higher quality (advertised as 1 million hours MTBF), faster 7200 disk speed and the fact that they are NAS drives. I had to call Promise during the installation (ended up my ASUS thunderbolt driver wasn't installed) and told them the drives I had installed and they didn't have any issue with it other than a customary warning that they are untested. The support received was excellent and once the driver issue was resolved the technician stayed on the phone and showed me how to set up the raid and got things running (service a step beyond my expectation). I realize I have taken a small risk with these drives, but so far it is running like a charm.
While 4 disks won't saturate a USB 3 connection let alone a thunderbolt 2 link, I wanted to try this technology and the R4 fit my budget. So far I couldn't be happier. If you want performance information, there are plenty of tests out there that would be far more informative than I can produce - just google search for them. I found two items that a new user should be aware of - the windows instructions say you must have the latest firmware so make sure you update the unit with their software (quite easy to do, just look around for it). The second item says to log on use your windows ID and password - this is incorrect and will not work so don't spend a lot of time on it. Hopefully they update their instructions on this soon.
I hope this information is helpful to anyone thinking of going this route.