Nehalem: The new standard for energy efficient performance

The Intel® Xeon® 5500 Series Processor (aka Nehalem) officially stepped out from behind the curtain onto center stage today.  This processor is an engineering marvel…one that can intelligently provide phenomenal performance on demand, while also sipping power when not in use.

Any measure of energy efficiency consists of performance in conjunction with the amount power consumed, so let’s cover these “big” items first.

  • Performance:  As of March 30, 2009, Intel based 2 socket Xeon® 5500 series servers set at least 30 world performance records across a wide range of benchmarks that cover virtually every application type on the market. The performance results, just by themselves, are utterly amazing, and in general they are greater than 2x the Intel® Xeon® 5400 series processors (Harpertown).
  • System level power consumption:  The electricity bill is based on how much power the server consumes, so that is also an important part of the energy efficiency equation. In general, Intel® Xeon® 5500 (Nehalem) based servers consume equal or slightly less power under peak workloads vs. previous generation Intel® Xeon® 5400 based servers.  By increasing performance more than 2x over previous Intel server processors while keeping overall power consumption in check, this is a great recipe for energy efficient performance.  In addition, when servers are at idle or are not fully utilized, customers want them to consume the least amount of power possible. Because of some key new power management features built into Nehalem, system idle power is dramatically lower (up to 50% less) than previous generation Intel® Xeon® 5400 based servers.

Now let’s get into three of the “behind the curtain” details of how some of the energy efficiency improvements are achieved.

  1. Power gating:  When a core is inactive, the operating system can request the core to enter a deep C state. Xeon® 5500 series processors supports C6, which is called “power gating”. This essentially puts the core into such a low power state that it consumes very close to 0W when not in use.
  2. DIMM memory power management: Today’s servers often have a lot of DIMMs installed, but leaving them in their full power state all the time isn’t a very wise. The Xeon® 5500 processor can intelligently reduce DIMM power consumption when not active by using techniques such as clock gating (CKE) and putting the DIMMs in “sleep state”, called self-refresh.
  3. Increased # of performance states:  P-states enable the server to proportionally match the power consumption of the server to the desired performance output. For example, if the processor CPU utilization is less, the operating system may request a lower P-state. By doing this, the power consumption of the processor is reduced to match the lower performance required. All this happens dynamically and allows the processor to scale both performance and power up and down to intelligently meet the workload demands.

In summary, while it is interesting to get into these “behind the curtain details”, what matters most is the performance and power at a system level. Servers based on Intel® Xeon® 5500 Series Processors represent a quantum leap forward in terms of both performance and energy efficiency! Call up your favorite server vendor and “test drive” one today to see for yourself.  And…once you get your hands on one, let me know what you think.