AIX 5.x, 6.x and 7.x Facts and Features

Check the IBM Link :

POWER5:
SF means "Squadrons Firmware".

POWER6:
EH is Enterprise High-End
EM is Enterprise Mid-Range (formerly Intermediate-High)
EL is Enterprise Low-End

POWER7:
750 and 755 should be AL and 770/780 should be AM.
775, 790 and 795, or whatever comes out for the ultra high end would be AH.



http://www-03.ibm.com/support/techdocs/atsmastr.nsf/fe582a1e48331b5585256de50062ae1c/90aab55658365a5f86257178007322a3/$FILE/AIX%20Facts%20&%20Features.pdf