I've updated the firmware on my router to the latest version of Jonathan Zarate's Tomato firmware plus Rodney Chua's SpeedMod patches. That seems to squeeze out the best performance from my Linksys WRT54GL:
VirtualBox is at 3.1.2 but I just cannot get a stable host system with the 2.6.31* Karmic kernels. I also think setting the network adapter to use the virtual Intel PRO/1000 device causes instability too. There are no problems with a 2.6.31 kernel and VirtualBox on my backup server. That may be down to it being a 32bit host install - this is on a 64bit Athlon II machine - but I still can't pin down a cause.
-- MartinRowe - 14 Jan 2010
Still getting the occasional page allocation error even with the old kernel from Jaunty. Updated VirtualBox to 3.1.0 without any improvement, so trying again with 3.1.2.
-- MartinRowe - 2 Jan 2010