Both are good boards. The GA-990FXA-UD3 r5 rev 1.0 is the newer model that's all and has the upgraded sound chip. Other wise both have the same features. With that said and if you all ready have an AM3+ CPU and looking for a new board I'd go with the GIGABYTE GA-990FX-Gaming if your budget will let you. It's only $20 more and has some really nice newer features like a M.2 slot, USB 3.1, and USB 3.1 Type-A. The GA-990FX-Gaming probably be the last if not only 990FX motherboard released with these features which would get you buy 1 to 2 years until you decided on a new system build.