IBM had two distinct POWER- and PowerPC-based hardware lines since the early 1990s: After the introduction of the POWER4 processor in 2001, there was little difference between both the "p" and the "i" hardware; the only differences were in the software and services offerings.

With the introduction of the POWER5 processor in 2004, even the product numbering was synchronized.

In April 2008, IBM officially merged the two lines of servers and workstations under the same name, Power,[2] and later Power Systems, with identical hardware and a choice of operating systems, software, and service contracts,[3] based formerly on a POWER6 architecture.

[4][5][6] AIX and IBM i continue to run in big-endian mode.

IBM Power Systems models: IBM PowerVM provides the virtualisation solution for Power Systems servers.