AMD plans to introduce three 9-series Northbridges and two 9-series Southbridge chipsets in the second quarter of 2011, according to a report by X-bit Labs. These chips are designed for the Bulldozer architecture and will be part of AMD's Scorpius enthusiast desktop platform. Which sockets motherboards based on these chips will have is still unknown, but it will likely be a AM3+ socket with backwards compatibility for current-gen AM3 chips.
One of the major new features is IOMMU, a new technology that seems primarily intended for improvements in heterogeneous computing on the desktop platform:
Like a traditional MMU, which translates microprocessor's virtual addresses to physical addresses, the IOMMU maps device-visible virtual addresses to physical addresses. The I/O memory management unit provides a secure, scalable, high-performance solution for I/O virtualization in client or server computers.
Here's an overview of the three AMD 9-series Northbridge chipsets:
AMD 990FX - supports two PCIe 2.0 x16 slots (configurable as four PCIe 2.0 x8), six PCIe 2.0 x1 slots, one PCIe 2.0 x4 slot, to be paired with SB950 I/O controller;
AMD 990X - supports one PCIe 2.0 x16 slots (configurable as two PCIe 2.0 x8), six PCIe 2.0 x1 slots;
AMD 970 - supports one PCIe 2.0 x16 slot, to be paired with SB950 and SB920 I/O controllers;
And these are the two new Southbridges:
AMD SB950 - four PCIe 2.0 x1 slots, 14 USB 2.0 controllers, PCI bus, six Serial ATA-600 connectors with RAID 0, 1, 5, 10 support;
AMD SB920 - two PCIe 2.0 x1 slots, 14 USB 2.0 controllers, PCI bus, six Serial ATA-600 connectors with RAID 0, 1, 10 support;