Switch your driver to compute mode?
I didn't know that there is an option for this. That really helped, thank you!. Now it's 22.5 Mh/s. Is this a limit for this card or I can improve this without flashing BIOS?
You can only OC memory, or try to play with -dcri value
Also, try to put -asm 2 in command line, works better for some cards