slow image rendering in F15 for firefox and image viewer

[James Bridge]

Hope I'm not going over old ground...

I have a clean install of F15 on an x86-64 desktop, with no non-free
apps except for Adobe flash. Basically trying to get the hang of Gnome
3!

Compared to F14, viewing jpegs with "image viewer" seems much slower
than it was, though Shotwell seems to perform normally. Firefox also
slows down badly if a page with images is zoomed, unless I select the
option to zoom only the text. Chrome doesn't have a problem

I'm guessing here - is this something to do with the way with firefox
and image viewer use nouveau? Is it a bug or what?

-- 
James Bridge <james at xmas.demon.co.uk>