Asus "Computing Flyer" contained some interesting tidbits of information about upcoming chipsets from AMD, something you wouldn't expect to find in marketing material way ahead of chipset launches.
The RD790 is far from a secret as there are boards based on this dual x16 PCIe chipset all over the show. It is the first Hypertransport chipset from AMD, but it has several siblings.
First up is the RD780, which is a dual x8 PCIe chipset and it supports socket AM2/AM2+ and has HT3 just like the RD790.
Then there is the RX780, which only supports a single x16 PCIe slot, the remaing features are the same as the previous two chipsets.
All three will be paird with the SB600 south bridge and will support DDR2 1066 memory as well as PCIe 2.0.
The board below is the M3A which is based on the RX780 chipset.