You can google Netsurf Atari Falcon and find out that it load much faster with Atari. There is two possible reasons, Atari is so much better than Amiga or There is a proper port of Netsurf for Atari.
68k version is based of framebuffer version of netsurf, wich is meant to be used for debuggin or no gui systems. It also runs top of the SDL.
I get 6.6s on my 600MHz SAM440 with the native frontend. To find out if framebuffer is the problem you'd need to run OS4 and the native frontend on the Amiga in question and see if the times improve. Although then you'd be changing *everything* so it might not be a worthwhile comparison.
It is actually not mentioned whether the PPC boards are running OS4 and native NetSurf - given that there is no horrid framebuffer build for PowerUP/WarpOS then the fact these boards are PPC would be irrelevant.
Possible reasons for slowness are CSS selection (a known problem, due to be improved for 3.2) or page rendering (this is what would cause a big difference between framebuffer/SDL and any native frontend - the OS4 one uses graphics.library directly), along with network (already mentioned).
