32bit OS on this board? Don't be daft..
Of course six memory slots is a good idea. Whilst you can run XP on this hardware, it's more suitable for running Vista x64 or a 64 bit Unix. As soon as that sort of market is targeted a minimum of 4GB (especially for Vista) becomes a very good idea.
Given that the maximum memory for 975, X38 and X48 chipsets is 8GB this needed to change. Run a couple of virtual machines, some heavy photoshopping or video editing and it's not that difficult to break the limit.