Well thanks to llasram my tocs now load instantly for my epubs. After removing the fragment identifiers (which aren't needed in any of my epubs as far as I can tell) it's now not an issue
As to the slow chapter loading well as I said in my previous post it doesn't seem to affect me at all so I'm not sure what's causing that. Chapters load just a tad slower than a page turn in all my books.
I've read over a 100 epubs on my 505 and the slow toc was the only issue I ever came across (and that's now been fixed with a little editing). The 505 seems to have plenty of power to me
At least for my uses.