Are you having to run AIX 5.3 to maintain legacy systems on old hardware?
Using AIX 5.3 Workload Partitions for AIX 7 you can now consolidate these workloads on to a single Power 7 server, reducing hardware and software maintenance costs and freeing up valuable rack space.
For more information, please the IBM website at:
http://www-03.ibm.com/systems/power/software/aix/sysmgmt/wpar/v53_wpar.html