Although having been anticipated for a late Q2 launch, it's become apparent that AMD's RD890D/SB850 chipset which will replace 790FX/SB750 won't be ready until sometime during the last quarter of this year, leaving 790FX/GX the only chipset to support AM3 based Phenom CPUs until its debut.
What is known about this chipset at this early stage is that AMD plans to focus it entirely around the AM3 socket with DDR3 support only and no AM2+ compatibility. Features of RD890 include HT3, 32 PCIe lanes (in a two x16 or four x8 arrangement) with enhanced quad CrossfireX support.
The SB850 Southbridge is known to have all features of the SB750 and then some, including Gigabit MAC, AHCI 1.2, new clock gen and second gen PCIe 4X.
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