RD890/SB800. The 890 is suppost to give you better overclocking with the 45nm. AM3 processors then the 700 series did.
And the SB800 moves the PCIe support from the northbridge to the southbridge. More USB ports support. Makes the jump to Sata 6Gb/s. All new Southbridge.
They were suppost to be released when the AM3 came out, but the processors got out the door first, the drop to 45nm. went better and faster then AMD thought so the chipset is taking alittle longer.