OK well from what I hear NVME drives are faster than SATA III drives for booting. As I say, not tried it myself but I know that my RAIDR was always faster (timed) than any of my other SSDs for booting. Only a few seconds, and not really something I would have noticed unless I timed it but NVME drives at reads are three times faster than my Asus RAIDR so I guess you would definitely see a marked difference coming from an old drive !
The booting part is the only part I am not sure about yet. Some say some cards are not bootable but can't offer me any information.
I am not sure if the boot bios is on the NVME stick or the sled yet. I would imagine it's on the stick (the drive) but yeah, not 100% sure. I was going to get one this month but because the RAIDR was a simple swap out it's kept the wolves at bay for a while
http://www.ebay.co.uk/itm/Up-to-330...417468?hash=item33c39163bc:g:oU4AAOSwHMJYJ67L
If I go that route I will get that and try it first. I have heard they get a bit warm, so liked the idea that that one comes with a heatsink.
Edit.
Having read the ad for it it does say this -
(Note: Due to computer BIOS limitation, not all motherboards support start function, please consult your motherboard vendor supporting details)
So I would imagine it is bootable, but as you know you need to mod your bios to make it viewable