0x20 0010 0000
0x30 0011 0000
^
Which is Bit 4 or Ram IC 04 (Starting from Right to left RAMIC{0..7})
0x20 0010 0000
0x39 0011 1001
^ ^ ^
Which is Bit 0, Bit 3, and Bit 4 or Ram IC's 0,3 & 4 (Starting from Right to left RAMIC{0..7})