? It's just a name that's different. The chips are basically identical.
Essentially the same chip binned lower. If you overclock both you might get 0.1 Ghz less out of the 8320 which is insignificant.
It's cheaper and essentially the same performance.
If you're looking for a mobo go with a 990 series rather than 970 for performance and reliability, as well as the possibility to overclock well.