Reliable, fastest page rendering, and never crashes on old hardware (iPad 3)

Im a medical student and I usually have books that are 500+ mb in size (Harrisons for example) and for most pdf readers they all render slowly (about 5 seconds per page) and crash when I browse too many pages. This one however never crashed on me, and renders each page in about 1 second. Amazing app

Jaye501st about PDF Box, v2.9.1