IBM is top dog when it comes to the UNIX market. According to IDC, its Power Systems (i.e., AIX, IBM i and Linux servers) grew UNIX server revenue in 2011 in what has been an overall declining market.
Power Systems can be split into two categories:
Power Express consists of five servers -- Power 710, Power 720, Power 730, Power 740 and Power 750. They range from 2U to 4U models containing a few cores up to systems with as many as 32 Power7 processor cores.
The Power 710 has up to eight cores and carries the lowest entry price of the Power7 servers. The Power 720 comes is a one-socket model that comes in a rack or tower configuration holding up to 256GB memory. The Power 730 comes with up to 16 cores to support virtualized applications and infrastructure. The Power 740 is a rack-mounted 2-socket (up to 16 Power7 cores) server with up to 512GB memory.
At the top of the Express line is the Power 750. It is characterized as a high-performance, reliable midrange server that supports database and line-of-business applications. It can be configured with up to 32 Power7 cores at 3.7GHz in a 4U rack-mounted server.
At the high-end come a new category of servers known as Power Enterprise with three servers available -- Power 770, Power 780 and Power 795. They provide up to 64 cores on Power 770, 96 cores on Power 780 and 256 cores on Power 795.
Other features include capacity on-demand processors and memory without downtime, Active Memory Mirroring of the hypervisor, and PowerVM-based virtualization
The Power 770 has up to 4TB of memory and is intended as a platform for consolidation of UNIX or x86 servers. A greater number of processing cores makes the Power 780 well-suited for large transaction and database serving.
King of the mountain is the Power 795, which takes advantage of 64-bit Power7 eight-core processor technology and up to 8TB memory configurations.