Originally posted by: j.gann
depends on your goals.
power4 will run aix and powerha up to the most current versions. lpars are possible, even though in an outdated fashion (dedicated cpu). On a tight budget I'd choose this for app-related tasks like development/sw test because here the ancient hw (out of sales for long) usually does not matter.
if "LPAR" means "virtualization" to you and you need to learn and test with current technology in-depth, do not waste your time with anything less than power5, better power6, budget permitting power7 (newer architecture, more and more advanced features).
hw reqs are detailed in every aix release's release notes.