There is usefull command called "prtconf" which displays the important system information.
Unfortuntley unless you have AIX 5 installed it doesn't display the processor speed!
$ prtconf
System Model: IBM,7026-6H1
Machine Serial Number: 6xxxxxx
Processor Type: PowerPC_RS64-IV
Number Of Processors: 6
Processor Clock Speed: 669 MHz
CPU Type: 64-bit
Kernel Type: 32-bit
LPAR Info: -1 NULL
Memory Size: 8192 MB
Good Memory Size: 8192 MB
Firmware Version: IBM,M2P030828_condor_
Console Login: enable
Auto Restart: true
Full Core: false
etc etc etc