Maximum memory capacity of AM3874 device - conflicting documentation!

We wish to attach 2Gbytes of DDR3 RAM to an AM3874 device, utilising 16bit devices to save board space. (Four 4Gbit devices in total).

The datasheet for the AM3874 (sprs695), section 8.13, quotes the maximum capacity memory device as 2GBit.

This conflicts with the AM3874 HRM (sprugz7), section 6.1, which shows a 15 bit address bus and a max page size of 2048 bytes. (Thus 4Gbit/device)

Could anyone explain this difference in documentation?

Can we use four 4Gbit 16bit RAMs with the AM3874 and access the full 2GBytes of ram?

Thanks,

Ian.