I have a rig with 12 GTX1070.
Six of them perform well, 26MHs without overclock, in ethereum
But the other 6 only perform 22MHs

The 6 slow cards are all micron memory.
From the 6 fast cards, there are 5 with samsung memory and 1 with micron memory.
So the problem is not necessarily the memory type.

I tried flashing the bios from the fast micron card to the slow micron cards, but the hashrate keeps the same.
There is another difference between the fast and the slow cards:
The fast cards have the subsystem 3773
The slow cards have the subsystem 3703

Any idea how to make all the cards run at 26MH without overclock (hopefully 31 with OC)?