Thx for your answer its strange because I had same probleme with rx480 Nitro + OC 8GB samsung.
Maybe I am doing something wrong ? I just copy the 3.2 straps to 1750 and 2000.
Is there other thing to modify in the bios ?
Ubermix 3.2 where is this straps dont find it in PBE thread ? I have see the 2.3 ligthmix.
Yeah you could edit lot of stuff, but the most important gain in hashrates are performance timings. If your card can't handle Uber-Mix 3.1 than 3.2 should be good, or you need to set lower memory clocks. If you can return the card, do it, the 3.1 is the best you can have, without it that's just little bit better than stock.
3.2 is somewhere in that thread in the end it was few days ago.