Ever since I started with my rig building, all my RX 580 have been able to achieve over 31 MH easily.
Yesterday, I had four (2 on the motherboard, two on risers) running at 31.6 MH.
Today, I finally received my frame, build it with 6 risers and the hashrate has dropped for most cards (5 out of 6) as you can see here:
https://image.ibb.co/dmtfmw/Capture_d_cran_2018_01_26_19_02_30.pngI'm using the latest AMD drivers, all their BIOS have been flashed, they're all set to "compute" in the AMD settings and the clocks and voltage are the same for all card. I restarted the miner with the same result (5 slow, 1 fast).
The virtual memory is set at 16 MB.
I thought it could be the power supply but I'm using only 850W out ot 1000W.
In short, I'm puzzled. Has anyone an explanation?