Remove parallax effect on a single section

Hi guys, i have 8 rows in the page builder for my one-page site and i tried setting a background image for each one. The problem is that seems like parallax is too heavy and while some not load properly making the effect “delayed”, others don’t show at all. Tried to use gif images cutting down the file-size without resolving the issue. Any suggestion to make the page more fluid? If there are no solution, how to disable the effect only for some rows? Thnx in advance for helping a noob like me ??