I can... usually get six keys but it's kind of finicky about which keys I'm holding when I press other ones and whether I press them at the same time or with a slight delay. I voted 5 in the poll because there are quite a few six-key combinations that don't work. When I press all eight at once, none of them are registered until I let go of some.
Razer BlackWidow, basic model, a few years old.
Razer BlackWidow, basic model, a few years old.