PiB vs computer memory unit

PiB and computer memory unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
PiB	Yes	No	No	No
computer memory unit	Yes	No	No	No

As nouns, computer memory unit is a hypernym of PiB; that is, computer memory unit is a word with a broader meaning than PiB:

PiB (noun)	computer memory unit (noun)
a unit of information equal to 1024 tebibytes or 2^50 bytes	a unit for measuring computer memory