In the latest JW update, the preloadAd feature was introduced. This feature loads the ad in the player before it is ready to play, creating an expected reduction in load time.

This will mostly benefit our 640x480 inventory and upcoming work adding playlists and related modules, as it does not work on autoplay inventory, unless that autoplay inventory reaches viewable browser standards. It is also only available for VAST ads, VPAID is excluded.