Get IBM Power system model in AIX

prtconf | head

Example output:

~ # prtconf | head
System Model: IBM,9131-52A
Machine Serial Number: 181DF2G
Processor Type: PowerPC_POWER5
Number Of Processors: 4
Processor Clock Speed: 1499 MHz
CPU Type: 64-bit
Kernel Type: 64-bit
LPAR Info: 1 10-0DE5G
Memory Size: 7904 MB
Good Memory Size: 7904 MB