Intel has unveiled its latest Xeon series of CPUs for servers and workstations. The Xeon 5500 series was formerly codenamed Nehalem-EP (Efficient Performance), and is related to the Nehalem CPUs used in Core i7 desktops.

The 5500 series features quad core processors built on a 45nm process using Hi-K metal gate technology, as found on the Core 2 Duo and Core 2 Quad processors. Some models use Intel's Turbo Boost technology to operate one or more cores above the rated frequency to speed specific workloads. For example, the W5580 can be boosted from 3.2 GHz up to 3.33GHz, as long as power consumption and heat is within limits. Intelligent Power technology is also used to reduce power consumption during low utilization periods by shutting down unused cores.

This is achieved through the use of Integrated Power Gates, which allow individual idling cores to be reduced to near-zero power consumption independent of other operating cores. Intel claims this reduces idle power consumption to 10 watts, versus 16 or 50 watts in prior-generations of Intel quad-core processors. This feature is said to reduce server idle power consumption by up to 50 percent versus the previous generation of two-socket server processors.

The Xeon 5500 series is supported by the new Intel 5520 chipset, formerly codenamed Tylersburg-EP, available with the new Intel 82599 10Gb Ethernet controller. The chipset can support up to 18 slots of DDR3 DIMMs, and utilize up to 144 GB of DDR3 memory.

QuickPath Interconnects and an integrated memory controller are touted to speed traffic between processors and I/O controllers for bandwidth intensive applications. The 5520 chipset is being touted as future-proof, with drop in support being the target when Westmere-EP Xeons arrive in Q2 of 2010.

Intel's Pat Gelsinger, Senior Vice President and General Manager of the Digital Enterprise Group, gave the Xeon 5500 launch presentation. The improvements in efficiency and performance were highlighted repeatedly.

He used the example of 184 Intel Xeon single core servers from 2005 in a datacenter, now due for replacement. They could be replaced by 184 Xeon 5500 based servers for a 9X performance gain with an 18% reduction in annual energy costs. Alternatively, they could be replaced by 21 Xeon 5500 servers which would provide the same level of performance, but at a 90% reduction in annual energy costs. They would result in an unprecedented eight month payback period based on those saving.

Datacenters consume a tremendous amount of power not only for the servers themselves, but also for cooling and humidity control. Heat is produced by the thousands of CPUs in a datacenter, but there is also a large amount generated by hard drives, routers, switches, and Uninterruptable Power Supplies.

Intel is positioning the Xeon 5500 series for the expected growth in cloud computing and virtualization. Key adopters are firms like eBay, Amazon, Microsoft, Google, Sun, and Yahoo! Companies like OnLive are also expected to make heavy use of these servers to provide gaming and entertainment services to customers.

Intel will show off an eight-core Nehalem-EX Xeon at the Intel Developer Forum this September. Westmere based Xeon servers will also be unveiled next year.

For performance figures on Intel's latest server processors, you can check out AnandTech's review.