AMD CPU Chipsets
Most of the modern AMD chipsets now come in an AM3 flavor - what that means is that the motherboards use DDR3 and ONLY AM3 CPUs can be used in them. This get's confusing and we really don't want to be confused, do we? For new AMD builds, you will probably want AM3 and DDR3 now. Don't be confused by boards that SUPPORT AM3 CPUs but are really AM2+ boards.
AMD 890GX
This AMD chipset supports crossfire at x8/x8 and SATA 6GB/USB 3.0. It also has a very slight onboard graphics improvement over 790GX, depending on who you ask. Unlike the Intel P55 boards, the 6GB SATA does not take away from the PCI-E slots... making this a better gaming choice in some ways.
AMD 890FX
Like the 890GX only with more PCI-E bandwidth for those demanding crossfire video cards. The extra bandwidth might not be needed, but since these are more deluxe boards they can be worth a look.
AMD 870
Will normally have just one PCI-E slot and no onboard graphics. A great budget choice.
AMD 790GX
An older chipset, but still many sold. Much like the 890GX but with no support for USB 3 or SATA 6GB/S
AMD 790X
Like the 790GX but without the onboard graphics.
AMD 790FX
A bit more pricey that the 790GX, this board had more features but no onboard GPU. Most of the deluxe AM2+ or AM3 boards fell into this category. PCI-E 2.0 @X16 in crossfire. Similar to an X48 board, but for AMD CPUs.
AMD 780G
Older board with just one PCI-E slot for video card.
AMD 785G
No large changes over 780G, but it's newer and may support some current CPUs better. Comes in both ATX and micro-ATX sizes and is budget friendly. Some increased onboard GPU functionality.
AMD 770
An older budget chipset, no graphics.