7970 vs 7970GHz vs R9 280x (7970 BIOS)

[chestwood96]

Dont get me wrong this is not a what to buy thread

I am planing to mine on a 7970 (Mostly Altcoins).
Since these 3 cards have completely identical Hardware (just different bioses) i am triing to decide wich to use.

Now my question is wich gives me the best performance for mining i used it as a GHz for gaming but wich one is best for mining?
I have tested all of the bioses and they are working perfectly(for gaming).

Sorry for my english guys
(i have posted a similar questions on the doges.org forum but no luck there)

[QNX]

each bios can have a different memory timing setting, so it's possible that 280x bios will be worse, than stock 7970 for example on gigabyte 7970

[chestwood96]

I have the Gigabyte 7970OC Windforce and i am using all the gigabyte bioses (since they are all exactly the same card)