Got my 580x working with --asm yesterday, uninstalled previous drivers with AMD cleaner tool, then reinstalled latest blockchain driver, so looks like my --asm problems was driver related. (i already had the same blockchain driver installed, but did not use the cleaner tool before installing it the first time)

Now i can run 3x 580x 4GB with --asm -i22 --auto-gpu without issues, -i23 still gives -error4 though.
I can run with -i23, but then I have to run 2 separate instances of mkxminer, and it won't always start the second one, so for now i just run with -i22.

Looking forward to being able to mine any pool 
Great work!

Anyone tried with 370x? What hashrate is it running at?

Getting 20-22mhs with my old 280x, and in my other computer with 3x 580x i'm only getting 30-32mhs each, not very impressive considering the hashrate I get from my old 280..
--asm just crash the gpu's and give a black screen, have to reset manually, is there a way around this or is there a problem with the gpu's causing this, since it's says it might cause problem with ellesmere cards (why just some and not all?)
Running +10 power limit and 1250/1250 core/memory now 8 hour stable with -23 intensity, but can't run 3x cards in 1 miner window, that gives error -4 with I23, but if I run 2 miner windows, one for gpu 0,1 and the other for 2 it works with I23.
A little disappointet, as it says 39mhs for 580x