Interesting that you obtained strikingly different quality on the same page on different occaisions.
Two things I can think of to look at. Pay attention to what you have running at the same time. Close everythings else that can be closed and make sure you don't have any apps running in background. And see if clearing your browser cache makes a difference.
I assume you were using the same browser, but you might compare to see if hotspot browser gives different results than internet browser.