Video lags in preview

hi, im new here. my laptop is about 7 yrs old , is that why the video lags. any way to make that better.
trying to edit mov files filmed in 1080.
how come my computer will play the video smoothly but shot cut wont play it smooth

Does your laptop meet the shotcut requirements?

Have you tried under Settings/Player putting a check mark in front of Realtime (frame dropping) ?