It should be smoother that 0.5s flash, I don’t think I had this issue with .pdf and I’ve tested even the bigger ones that you’ve mentioned in your previous topic.
Could you please double check that you have IE11 installed with the correct entries for browser emulation? (in the correct path on your machine 32/64)
While you’re in registry, you can also enable this Feature/Bugfix inside: Activating GPU accelleration for Xibo for Windows Player / Solution for Slow Stuttering Marquee Ticker & Effects
(not specifically for .pdf but might help).