No need for command line. Just edit config.txt and you can use my config. I get 26,7 MH/s with modified BIOS:

"
-pool ssl://eu1.ethermine.org:5555

-wal YOURWALLET.%computername%

-amd
-clgreen 1
-astats 1
-gbase 0
-mt 2

-acm
-leaveoc
-altinit
-powlim -20
-tt 64
-tmax 66
-fanmin 65
-fanmax 95
-fcm 2

-tstop 70
-tstart 55

-cclock 1070
-cvddc 800
-mclock 1800
-mvddc 875
"