step up vs intensify

step up and intensify both are verbs.

Word	Noun	Adjective	Verb	Adverb
step up	No	No	Yes	No
intensify	No	No	Yes	No

As verbs, step up and intensify are synonyms defined as:

Other synonyms of step up include escalate.

step up (verb)	intensify (verb)
increase in extent or intensity	become more intense
speed up	make more intense, stronger, or more marked
make oneself visible; take action	increase in extent or intensity
	make the chemically affected part of (a negative) denser or more opaque in order produce a stronger contrast between light and dark