https://i.imgur.com/E0gIUoS.pngYou need only Phoenixminer. I use the recent drivers, there's no point for blockchain anymore. (AFAIK)
You need to mine individually for several minutes to know the overclock for each one and take notes.
After every cards is on, figure out what is gpu 0,1,2,3,4,5 by starting each one individually (gpuz will tell what card is on if you are a remote controller), if your cards are really identical, gpuz will not help and you need to be present. Set fan to 90 and use your eyes.
Then just put the numbers of each one and your command line will look like this: (only 7 cards here).
"-FANMIN 70,50,50,70,90,70,50 -FANMAX 90 -CCLOCK 1250,+150,+150,1250,-400,1250,+150 -MCLOCK 1800,+400,+400,1800,+300,1750,+400 -CVDDC 760,0,0,760,0,760,0 -MVDDC 0 -TT 75 -HSTATS 2 -PROTO 4 -POWLIM 0,-33,-33,0,-40,0,-33 -straps 2 -gser 1 -coin eth" - Go to phoenixminer page here and read all commands, there's a lot of cool things
A rig with only AMD will be simpler
Obviously for overclocking HIVEOS is hella easier but have its own problems.
I have one RIG with 20.11.2 and two using 20.12.1 (for non specific reason), I don't know what driver is the best, i'm returning to this world now and i need to re-learn.
Windows crash is often overclock, one of them is above its capacity. Incorrect/reject shares are a hint.
High temp in one card may causes crash, the card reduces their clock automatically. Low virtual memory, ram memory or disk space may cause cashes when DAG is rewritten. Another software running in the background like windows update may causes crash too. You should be able to use your browser while mining without crashing, this is a good test.
Sorry for bad english.