A stock Rx 480 8GB does 30-34 Mh/s with the newer Lyra2v2 miner in my testing, Rx 470/570s do 22-26 Mh/s using the same miner. I'm not sure why the difference between different GPUs of the same series since I don't think the memory type matters for that algorithm. It's fairly competitive imo... higher avg hashrate then the GTX 1060 series at the cost of a little more power.
That's a massive improvement, then, making the RX 570 roughly comparable to a GTX 1060, based on my notes. Still nowhere close to the 50MH/s I get with a plain 1080 using one of the many ccminer forks (polytimos - pulled from NemosMiner so not sure of actual version, etc.).
The new Claymore Neoscrypt miner is pretty good too - if you increase the power limit you get quite high hashrate, but I prefer to leave the power at stock.... stock Rx 480 8GB does 860 kh/s (can be tweaked higher) and Rx 470/570 does around 740-750 at stock settings. The good old Fury X does 1550-1600 kh/s at stock and 1190 kh/s at -50% power.... I don't have any Vega GPUs, but people report 2000 Kh/s with that new miner.
So, Claymore's Neoscrypt miner is maybe 3% faster than Gateless Gate, before subtracting out the devfee. I use his Ethash miner because it is by far the fastest and most stable, but try to use any miner besides his for the other algos because he's turning into the Bitmain of GPU mining software.
Does anyone have another algorithm that AMD is at least semi competitive with?
I'm willing to do testing of pretty much any algo if I there is both a miner and at least a Windows cli wallet available. All I have are 4x RX 560 on one rig and a single RX 570 on another, though.