AZW is clearly not PDF based. Try opening an actual PDF on a Kindle and compare the experience.
I had a 12y old Paperwhite 2gen and have an 11th gen one.
PDF were just not meant to be viewed on the old one, but the 11th gen handles them surprisingly well.
alt Hacker News
I had a 12y old Paperwhite 2gen and have an 11th gen one.
PDF were just not meant to be viewed on the old one, but the 11th gen handles them surprisingly well.