1st time builder. have a asus maximus vi extreme. my questions are all pcie ssds bootable? for my operating system? how do I know?. can someone explain the advantage of the ngff m.2 on the extreme and how best to use it....can I boot from that? any recommendation for size of bootable operating system(windows7 64 bit pro) ssd hardrive(I plan on installing all other software on a secondary ssd drive)