Building an Extremely Power Efficient Intel Sandy Bridge Desktop System

Since I have a 3.15Kw grid-tied Solar PV System on the roof of my house in Parker, I pay pretty close attention to my electrical power usage. I try to generate more electricity than I use, because I care about the environment and because I hate my electric company (Intermountain Rural Electric Association – IREA) with a burning passion. At the same time, I like computers and consumer electronics gadgets, so I carefully choose components to minimize electrical usage while still giving excellent performance. This also give me another excuse to upgrade more frequently!

My latest project was replacing my girlfriend’s two year old desktop machine with a new Intel Sandy Bridge system. One trip to my local Micro Center gave me all the parts I needed to build this system. Micro Center is a great resource if you are lucky enough to live near one, since they often sell loss leader components that are significantly cheaper than NewEgg. Of course, it can also be dangerous, since it is easier to go there and spend money…

The new system uses half the power and has more than twice the performance on Geekbench. It also feels much faster subjectively,in day to day usage, due to the SSD and the incredible Sandy Bridge processor. My girlfriend even noticed the difference! Here are some details, and performance numbers for both systems.

Old System

The old system (which I built), had a 45nm, 3.0GHz Core 2 Duo E8400 processor in an ASUS P5Q-SE motherboard with 4GB of DDR2 RAM, a Sparkle 9500GT fan-less video card, a 500GB Western Digital GreenPower hard drive, and an Antec Earthwatts 380 watt power supply. The CPU-Z info for that system is shown below:



Old System CPU-Z Information


This was the 45nm, Penryn die shrink version of the original Core 2 Duo processor. I purposely tried to minimize the electrical power usage of that old system when I built it, and I did a pretty good job with what was available in early 2009. This system used 60 watts at idle and 101 watts when the CPU was pegged during a Geekbench run, using the Balanced Windows Power Plan.



The Windows Experience Index (WEI) for the old system was 5.0, being held back by the 9500GT discrete video card. The Western Digital GreenPower hard drive was also a weak point from a performance perspective.



The Geekbench score for this “old” system was 3427, which was pretty respectable. For you eagle-eyed readers, you might notice that I had 8GB of RAM in the system when I took this screenshot. Going from 4GB to 8GB of RAM had no effect on the Geekbench score, although it did increase electrical usage by a couple of watts.



CrystalDiskMark shows the relative weakness of the older 500GB Western Digital WD5000AACS GreenPower hard drive. The newer and larger GreenPower hard drives do perform quite a bit better than this model.


New System

The replacement Intel Sandy Bridge system has a 32nm, 3.3GHz Core i5 2500K quad-core processor in an ASUS P8H67-M Pro motherboard, 8GB of DDR3 RAM, with an 80GB Intel X25-M G2 SSD, and a Seasonic X400 modular, fanless power supply. I wanted to use the improved integrated graphics in the Sandy Bridge, which means that you have to use an H67 chipset, Socket 1155 motherboard (instead of the enthusiast P67 chipset). I also wanted the better HD3000 version of the Sandy Bridge integrated graphics, which is only available in the unlocked K version of the desktop Sandy Bridge (such as the Core i5 2500K and the Core i7 2600K). Using integrated graphics would save power and save money on parts. The Seasonic X400 has an 80 Plus Gold efficiency rating,and is modular so that you have less cable clutter in the case. I had the 80GB Intel SSD just laying around, so I figured it would get the job done. A Crucial RealSSD C300 would perform much better, especially with the 6Gbps SATA support on this motherboard.

At any rate, the new system draws 29 watts at idle,and 86 watts when the CPU was pegged during a Geekbench run, using the Balanced Windows Power Plan.  This is a huge improvement over the old system. I could probably reduce the power usage by several more watts if I disconnected one or more of the case fans, but I decided not to do that.



New System CPU-Z Information



The Windows Experience Index (WEI) for the new system is 5.7, being held back by the integrated graphics. The Intel 80GB SSD is pretty speedy.



Geekbench score is more than twice as high as the old system.



CrystalDiskMark shows the performance of the 80GB Intel X25-M G2 SSD. It is relatively weak on sequential write performance.

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7 Responses to Building an Extremely Power Efficient Intel Sandy Bridge Desktop System

  1. Matt Velic says:

    That’s an impressive new build. But do you find Micro Center to be cheaper than NewEgg? The one in my area (Washington, DC Metro Area) seems to be well above the NewEgg prices with much less variety. Maybe it’s just my store though.

    • Glenn Berry says:

      It depends what you buy. Micro Center has certain items that they sell as loss-leaders (such as processors) that can be significantly less than NewEgg.

      I really like having a Micro Center so close when I need parts.

  2. Mike says:

    Hi Glen
    I am looking at setting up a similar setup as this to use as a learning/training/experimentation environment, also trying to keep costs down.
    I plan to run windows server 2008 R2 enterprise edition (Using my MSDN Subscription) with up to 3 VM’s to experiment with things like SQL mirroring etc. Would this machine setup be good enough for this purpose or would I need to get something using a server class chips such as a Xeon?
    I would also want to implement something like a RAID 1 would “Intel Rapid Storage Technology” available on some of the Asus motherboards do?

  3. Glenn Berry says:

    I have had driver problems with at least one ASUS Sandy Bridge motherboard, when I tried to install Windows Server 2008 R2. The OS install disk did not recognize all of the devices, which is no surprise (even with the 2008 R2 SP1 slipstream version). The drivers from the ASUS web site had version checks that would not let them run on Windows Server 2008 R2 (even though they run fine on x64 Windows 7).

    I just built an MSI Sandy Bridge system, so I will try installing Windows Server 2008 R2 on that tonight. In the meantime, you might be better off with an X58 based Core i7 system, with six memory slots. That will have plenty of CPU power for testing, and no driver issues.

    • Mike says:

      Thanks Glenn

      I will look into I7 a little more. price wise they look very similar but I would lose the performance of the 2600k compaired to the 2600k at the same price point.

  4. Jack says:

    I am very interested in the power consumption you’ve measured because I want to build a Sandy Bridge system for 24×7 use, and so a few Watts here and there can really add up.

    When you state power consumption numbers, are they measured at the wall socket (with a Kill-a-Watt, for example) or at the output of the Antec power supply? If they’re measured at the power supply output, you need to multiply them by 1.25 (1.0/0.8) to get the power you’d be drawing from the wall socket and hence from your solar cells.


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