Introduction and Specifications
It has been quite a while since AMD launched a new high-end desktop chipset. The 790FX has been riding high at the top of AMD's line-up for over two years now. It has been paired to newer Southbridge chips and AMD did follow up with the 790GX about a year and half ago, but for all intents and purposes AMD's flagship desktop chipset has remained unchanged for what is equivalent to an eternity in Internet-years.
Today, however, a new chipset will finally supplant the 790FX/GX at the top of AMD's line-up. As its name suggests, the 890GX features an integrated graphics core, but there's more to the story than just graphics. AMD has specifically stated that the 890GX will officially support upcoming 6-Core Phenom II X6 processors, and courtesy of a new Southbridge, the SB850, the AMD 890GX is the first core logic chipset to natively support SATA 6G.
We've got a couple of AMD 890GX based boards in-house for testing from Asus and Gigabyte, and have a full performance review posted on the pages ahead. First up, a little background on the chipset itself, and then we'll move on to the actual hardware and its performance...
AMD 890GX Chipset Block Diagram
Above is a high-level block diagram of the new AMD 890GX / SB850 chipset. As you can see, the chipset supports AMD socket AM3 processors, including upcoming 6-core Phenom II X6 processors, and it features an integrated, DX10.1-class graphics core with 40 shader units and a 64 / 128-bit memory interface. The reference specifications call for a 700MHz GPU core clock, and the IGP supports AVIVO / UVD 2.0. We should also note that the graphics core within the 890GX is branded the Radeon HD 4290, but it supports Hybrid CrossFire modes with the Radeon HD 5450.
890GX-based motherboards will typically feature DVI, HDMI, and VGA outputs, but DisplayPort is supported too. Dedicated Sideport frame buffer memory is supported as well. In fact, the Asus and Gigabyte boards we tested were each equipped with 128MB of Sideport memory.
Other features of the 890GX chipset include 22 PCI Express Gen 2 lanes in the Northbridge, and full HT 3.0, 5.2GT/s link between the CPU and NB. A new interface with 2GB/s of bandwidth between the 890GX NB and SB850, dubbed Alink Express III is used here, and the SB850 features all of the typical amenities of a modern chipset, like USB 2.0, HD Audio, Gigabit Ethernet, PATA, and PCI are present. In addition, the SB850 also features an additional pair of PCI Express Gen 2 x1 lanes, along with the aforementioned, native support of SATA 6G.