Performance Improvements in 8.1.x release?

[hotngui]

I am starting to investigate migrating some code that uses 7.12.0 and it looks like there are some noticeable improvements in rendering lists of very large images. I could not find anything in the release notes for any of the 8.x releases that would account for this and it has me confused. I am coming the same code of mine which contains no changes.

What changed that would have improved the performance, especially when scrolling through lists of very large images being pulled from the disk cache.