Hi,
I have a rig with 6 x rx580s that started mining at 24Mh out of the box. I experimented with the bios a little bit, got it down to 12, now it's back at 24 and I am a little depressed as I can't get more than that and I tried for the last two days. I will appreciate all help, thanks.
You need to mod bios. Hynix s*cks it's very bad right now. You can find few good tutorials on youtube and lot of bad. Performance timings is the key. You should have at least 28Mh/s. PM me if you want timings or mod bios.