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Displaying articles for: May 2009

Configuration Matters - What Affects Server Power Consumption: Part 1

Following on from my first post I'll take a look at the affect hardware configuration will have on the power consumption of the enclosure.

To do this I went into the Blade Power Sizer and configured up two equivalent systems. I kept the enclosure configuration constant with just 2 x Virtual Connect 1/10 Ethernet Modules and 2 x Virtual Connect Fibre Modules just to simplify the example.

The Blade configuration was BL460cG1, 2 x 2.66GHz CPUs, 16GB RAM, 2x 1Gbit Ethernet, 2x 4Gbit Fibre Channel, 2x 72GB 10K SAS Drives.

Why did I pick BL460cG1, to be honest the actual server doesn't matter, what I'm trying to show here is that the hardware configuration can have a very significant effect on the enclosure power consumption.  The nice thing about the BL460cG1 for this purpose is that it shows this really clearly.



Configuration A

Configuration B


BL460cG1 x 16

BL460cG1 x 16


E5430 2.66GHz

L5430 2.66GHz


8 x 2GB FB-DIMMs


Base Ethernet

1GBit Dual-Port Multi-Function

1Gbit Dual-Port Multi-Function

Additional Ethernets



Fibre Channel

Qlogic 4Gbit

Qlogic 4Gbit


2 x 72GB 10K SAS

2 x 72GB 10K SAS




Ethernet Switches

Virtual Connect 1/10

Virtual Connect 1/10

Fibre Channel

Virtual Connect 4Gbit Fibre Channel

Virtual Connect 4Gbit Fibre Channel




Power Supply

HP 2250W x 6

HP 2400W HE x 4




Idle Power



100% Load




The difference between the two configurations is 798W at idle and 1,617W at high load, which is a huge difference.

Where is most of the power difference coming from, well there are 3 differences in the configuration:

  1. CPU - E5450 (80W TDP) versus L5450 (50W TDP)

  2. Memory - 8 x 2GB FB-DIMMs versus 4 x 4GB Low Power FB-DIMMs

  3. Power Supply - HP 2250W versus HP 2400W High Efficiency

The power supply is worth about 200W (25%) at Idle and 300W (18%) at full load on this configuration. So it's a significant proportion of the difference at the idle load.  At the high loads, though, the majority of the difference between the two configurations is coming from the CPU and Memory.  A standard FB-DIMM takes approximately 10W per DIMM so the difference between 4 and 8 physical DIMMs is roughly 40W per server, additionally a Low Power DIMM uses 2W - 3W less than a standard DIMM.

So what can I take from this example? 

  • System configuration matters. A lot.

  • At high loads the server power consumption is the main factor

  • At low server loads the enclosure becomes a larger proportion of power consumption.

 What are the practical steps I can use to reduce power consumption.

  • Use the lowest power cost effective processor

  • Use smallest number of largest physical DIMMs that are practical and cost effective.

  • Use the highest efficiency power supply that is available

Comments as always are welcome. Let me know where you want me to go as I continue on with this series.

Part 2 of this series is Applications Matter


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About the Author(s)
  • More than 25 years in the IT industry developing and managing marketing programs. Focused in emerging technologies like Virtualization, cloud and big data.
  • I am a member of the Enterprise Group Global Marketing team blogging on topics of interest for HP Servers. Check out blog posts on all four Server blog sites-Reality Check, The Eye on Blades, Mission Critical Computing and Hyperscale Computing- for exciting news on the future of compute.
  • I work within EMEA HP Servers Central Team as a launch manager for new products and general communications manager for EMEA HP Server specific information. I also tweet @ServerSavvyElla
  • HP Servers, Converged Infrastructure, Converged Systems and ExpertOne
  • WW responsibility for development of ROI and TCO tools for the entire ISS portfolio. Technical expertise with a financial spin to help IT show the business value of their projects.
  • I am a member of the HP BladeSystem Portfolio Marketing team, so my posts will focus on all things blades and blade infrastructure. Enjoy!
  • Luke Oda is a member of the HP's BCS Marketing team. With a primary focus on marketing programs that support HP's BCS portfolio. His interests include all things mission-critical and the continuing innovation that HP demonstrates across the globe.
  • Global Marketing Manager with 15 years experience in the high-tech industry.
  • 20 years of marketing experience in semiconductors, networking and servers. Focused on HP BladeSystem networking supporting Virtual Connect, interconnects and network adapters.
  • Working with HP BladeSystem.
  • Greetings! I am on the HP Enterprise Group marketing team. Topics I am interested in include Converged Infrastructure, Converged Systems and Management, and HP BladeSystem.
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