dell inspiron 5559 video-graphic stuff

i have a radeon card as part of the laptop. but the intel processor seems to be the active graphic card only. according to the store owner the radeon only kicks in under stress, he had a software that created stress and then it shows the radeon working, otherwise it would show 4 lines of gpu slots, and only 1 of them with the intel processor active, the radeon not active at all.

is that correct , what the store owner said ?