Boy, dumping the memory down to P0 saves A LOT of power.
RX 580, at 1240/1750 does 49.6Mh/s at ~100W per GPU (as per GPU-Z).
Rig has 3x 580, 1x570 and was doing ~530W at wall.
Entered memory P0 state, and lost ~20W per 580 according to GPU-Z. Wall power consumption dropped from 530 to 440W.
Performance dropped with ~0.6MH/s per card.
Best performance/power consmption seems to be around 1200-1250Mhz.
Getting 190.8Mh/s for 440W at wall with 4 cards.
RX 570 - ~45.9MH/s
3x RX 580 - ~49.08MH/s.
Core clocks are all 1240Mhz. Core voltage is ~0.875V-0.893V (2x 0.875, 1x0.887, 1x0.893V).
Raising core voltage to sustain 1280Mhz core raises performance to 50.45MH/s per RX 580, but raises power consumption by ~30W (from 440 to 470). So, 10% power increase for 1% performance increase.
Yeah this algo isn't about memory it seems. I also dumped my Vegas at 500 MHz and RX series at 300 MHz. No big difference in hashrate.
My rig have the following cards;
3 x RX 560 4 GB 18 MH/s
4 x RX 570 4 GB 39 MH/s
2 x RX 580 8 GB 43-44 MH/s
2 x Vega 56 85-86 MH/s
My total rig wattage is exactly 1000W at 470 MH/s. (Lower power consumption than at CryptoNight V8!). Because I have quite expensive electricity I have quite aggressive undervoltating, 820 mV at core for RX 570/580 and memory all down to 600 mV. The Vega's have like 880 mV at core and 800 mV at memory (can't set lower because restriction in drivers apperantly. At this rates the rig is rock solid stable, havn't crashed one single time since like the fork of Vertcoin.
Till now, with my expensive electricity 0.1268$ kWh it have been profitable, like 1.5$-0.3$ (yesterday), but not anymore. So now the fun is over
