I'm looking to have 4 rx 570s and 2 rx 470s
yeah, but you will need newer drivers, which could be a potential problem.
in windows, new drivers check signature, which is a problem if you bios-mod your GPUs.
16.9.2 driver (that does not check sig) will not work on 570ies
in linux, same, you will need 17.something amdgpu-pro drivers, 16.40 drivers would not work on 570/580.
other than above, it should be fine.
Newer drivers in order for the rx 570s to work? Or to have both rx 470 and 570 in a single rig?
So I can't bio mod my 570s ?
Will it work if I don't mod bios?
His info is outdated. There is a workaround to run 16.9.2 drivers on RX 500 series floating around in this forum now (which works), allows BIOS mods, 470/570 together, and even >5GPUs
very well may be as i don't check it frequently...but you might want to point to the info
EDIT: here it is...less relevant for me since i have 470 on Win/16.9.2 and 570 on Linux.
https://bitcointalksearch.org/topic/cracked-run-6-rx-580s-in-windows-10-1900035