Hi again
Alan - well, I'm running out of ideas - I think that w/ the second iPad showing the same DL speeds that my explanation of differences in the Wi-Fi radios likely applies; of course, does not explain the browsing activities variations that your describe.
You could go into Settings -> Safari and toward the bottom delete your history and whatever else seems appropriate - not sure that it would help. You could also install another browser(s) to see if the behavior is similar (I have a number on my iPad 2, including Puffin). Dave