gigahertz vs gigacycle per second

gigahertz and gigacycle per second both are nouns.

Word	Noun	Adjective	Verb	Adverb
gigahertz	Yes	No	No	No
gigacycle per second	Yes	No	No	No

As nouns, gigahertz and gigacycle per second are synonyms defined as:

Other synonyms of gigahertz include Gc, GHz, gigacycle.

gigahertz (noun)	gigacycle per second (noun)
1,000,000,000 periods per second	1,000,000,000 periods per second