So to understand the 890FX chipset from AMD, aimed at the more enthusiast PC user, all we simply need to do is tell you a thing or two about its features. The 890FX chipset consists out of two chips that are added onto the motherboard PCB. The Northbridge chip, which is called the 890FX and the paired (Southbridge chip) SB850. Together they form the infrastructure for all standard devices, connectivity and interconnect bandwidth.
The Northbridge chip primarily functions as a control HUB for your processor, memory and PCIe links towards your graphics chipset. It is the primary chip responsible for these functions, the FX (opposed to GX) extension however indicates that there is no IGP embedded into this ASIC which the GX versions do have.
The 890GX has many PCIe link available for your dedicated graphics (or other add-in cards). The chipset allows you to utilize two full x16 graphics cards, or even four graphics cars as they would run at x8 PCIe links.
Now there's more than the 890GX and FX chipsets as AMD also launched the 870 and 880G chipset. Below you can find a little chart showing the difference without hogging up a full page with explanations.
AM3 / AM2+
Hyper Transport 3.0 (5.2GT/s)
PCI Express 2.0 v1.0
Number of PCIe Ports/engines
x4 A-Link III
ATI Radeon HD 4290
ATI Radeon HD 4250
HD Post Processing
29 x 29mm
21 x 21mm
21 x 21mm
21 x 21mm
As stated this chipset also includes native support for SATA 6Gb/s for aggressive RAID and SSD configurations and most motherboards are expected to include USB 3.0 support employing the chipsets dedicated PCI express link and leading discrete USB 3.0 solutions.
New in the 890 FX chipset is IOMMU support. Not something that the majority of you guys would be interested in but it allows for virtual addressing of memory by system devices. This enables devices to use their native drivers in a virtualized environment for enhanced performance. In a non-virtualized environment, IOMMU provides memory isolation and protection capabilities - device access to system memory is vetted by the IOMMU such that critical/unrelated memory information (e.g. kernel pages, protected content ) can be protected, leading overall to a more robust system. With an updated Hyperlink (revision 3) we now can connect to the SB850 chip with a well-appointed 2GB/sec bandwidth (full-duplex). Let's have a look at the SB850 Southbridge chip.
MSI 890FXA-GD70 review Of course we were already fond of the 890GX chipset when it got released, but the FX chipset upped the ante a tiny bit more as next to the integration of SATA6G we see an increase in available PCIe lanes allowing 890FX motherboards to become very flexible in their bandwidth needs versus component usage. PCI-Express is key in the AMD 890FX release as we get PCIe 42 lanes at our disposal. Next to that, the chipset will be paired with the SB850 which we already covered in the 890GX review, it supports up-to 14 USB 2.0, up-to six SATA 6G ports and an integrated Gigabit Ethernet controller. This is the basis and infrastructure of your PC, the 890 FX chipset. It's that kind of flexibility that allows ODMs like MSI to make little gems motherboards out of that chipset. MSI's 890FXA-GD70 is loaded with features like the aforementioned, but also USB 3.0, automated overclock options and even five (physical) PCIe x16 slots and even core unlock functionality from within the BIOS.