The date on this thread is NOT comforting....
I just upgraded from a DIR-615 to a DIR-825 rev:B1 ver: 2.02NA and I have the exact same problem of slow connection through IE8 to the ADMIN pages.
The 615 worked like a charm for 3 years but it's getting slow when everyone is using it at the same time. And since we can see an iPhone4 in our household's near future... I thought upgading to Giga for the wired PCs and Dual Band for everything else was the smart move to make.
Well Internet gets in and out great but those admin pages take so long!... by the time it gets there some times I have to re-enter my password!
I called DLink Support and I was told to switch to Firefox as browser to communicate with the routeur. Like many here I am NOT willing to do that. I've had 2 routers before this one and IE caused no problems whatsoever.
Anyway, does anyone here have a better solution than changing the browser?... or returning the router?

thanks.