According to a BBC article Dell gave false information in some of its advertisements. They claim it was a genuine mistake in one of their sales brochures, but it didn't save them from being sued. This is not surprising at all, given the number of desperate lawyers in the US.
Talking of Dell, I am quite impressed by their marketing department, at least in the UK - most of the companies I have worked for here used Dell as their main supplier of both workstations and servers. I personally assemble my own machines, but businesses, apparently, prefer ready-made solutions.