execution speed vs swiftness

execution speed and swiftness both are nouns.

Word	Noun	Adjective	Verb	Adverb
execution speed	Yes	No	No	No
swiftness	Yes	No	No	No

As nouns, swiftness is a hypernym of execution speed; that is, swiftness is a word with a broader meaning than execution speed:

execution speed: (computer science) the speed with which a computational device can execute instructions; measured in MIPS
swiftness: a rate (usually rapid) at which something happens

Other hypernyms of execution speed include fastness, speed.

execution speed (noun)	swiftness (noun)
(computer science) the speed with which a computational device can execute instructions; measured in MIPS	a rate (usually rapid) at which something happens