T440S M.2/NGFF SSD Drives

[cardwel1]

OK, before I buy one of these, I want to be sure I know what I'm getting into. I looked at the user manual] and found several notes about the M.2/NGFF drive slots. It has two, in addition to a 2.5" drive bay. But... when I read the manual, it says:

M.2 solid-state drive for caching only

and

• If your computer is equipped with both a hard disk drive and an M.2 solid-state drive, do not use the
M.2 solid-state drive as a bootable device. The M.2 solid-state drive is used for “cache” function and to
support the Intel Rapid Start Technology.

and

• If your computer is equipped with both a hard disk drive and an M.2 solid-state drive, you are not
recommended to use the M.2 solid-state drive as a bootable device. The M.2 solid-state drive is designed
and developed for the “cache” function purpose only. If you use the M.2 solid-state drive as a bootable
device, its reliability is not guaranteed.

User Manual Link

My question is... why all of these caveats? Is there some sort of technical reason I couldn't or shouldn't use an M.2 drive as a bootable drive? Why have an extra slot then? Why would it be "unreliable"?

Could someone with some expertise about this sort of drive and/or Lenovo weigh in here? I understand that NGFF drives are new, expensive and at this point are often used for caching, but I'd guess that over time capacities will expand, and it would be nice to be able to upgrade down the road and move my boot/system drive over to a new SSD. But I'm not going to buy something that I can't upgrade.

[cb474]

You may want to take a look at this thread:

http://forum.notebookreview.com/lenovo/ ... novos.html