They are different products with different PCB designs ,parts used and different prices .
The care Gigabyte gives to a entry level product like the 970A_UD3 is less than for the other one.
When i got my sample i was surprised to see the HT speed ,which on other manufacturer boards with the same chipset was 2600 and the fact that the SLI stuff is not practically supported although others have made it available.It s not that i would use it though
The BIOS support was so good that my new FX 4100 (that replaced a X3 720BE) was throttling even when it was cold as ice.
I have had lots of issues with this board ,it s not even at the pinky of my 890GPA-UD3.
The OS takes a lot seconds to come up due to unknown reasons like my K9A2 Platinum used to do with a SB 600 southbridge ,the,AMD drivers are not detecting the SB id ,Etron drivers get randomly a yellow bang ,the HDD performance of my WD Black 750G was subpar until BIOS F8 ,the overclocking watch dog reverts settings out of the blue and the list goes on.
But if you think they are identical no problem from me ,if that makes you feel good.