Green Gigabit Network Switches

Are your network switches energy efficient? I thought mine were.

A couple of years ago when upgrading my network at home I installed some new 8-port D-Link Green gigabit switches. At the time I was mostly concerned with ‘jumbo packets’ and streaming media, the warranty, and the green stuff was just a nice bonus.

Recently though as I’ve been adding / changing network equipment, I’ve been going through the home network, benchmarking how much power is being used to try and minimize electrical waste. It’s kind of fun in a sad nerdy way.

Today I’m adding another 8-port gigabit switch to my LAN to be used as an iSCSI backbone. I thought about buying another D-Link green switch, but decided to take the scientific approach. Considering that my existing 2-year-old switches were ‘green’ already, this project yielded another big surprise.


D-Link 8-port gigabit green switch #DGS-2208D-Link 8-port desktop green switches
(one upstairs, one downstairs)

  • 8-port
  • 10/100/1000
  • MAC Address Table: 8k
  • Switch Fabric: 16 Gbps
  • Jumbo frame support: up to 9600 Bytes
  • Part #DGS-2208
  • Street Price: about $58
  • Limited lifetime warranty

These switches performed well for me and handled the job of streaming HD content and moving VHD and ISO files across the LAN with no problems. When I bought these switches 2 years ago, the box stated a power savings of up to 80%, which sounded greener to me.

TRENDnet 8-port gigabit green switch #TEG-S80GNEW SWITCH

TRENDnet 8-port desktop green switch
(being added as an iSCSI backbone on the LAN)

In the past, I wasn’t a big fan of TRENDnet. Their blue plastic hardware looked like something made by Fisher Price in the 70’s, but not anymore. These new switches have a sturdy metal housing, and I like them.

These two switches are very ‘apples-to-apples’ in network specs.


I intentionally benchmarked both switches at 75% capacity (6 ports used with 2 ports unused). The reason being, I don’t like to use all the ports in a switch. In case a port goes bad you still have a couple of extra ports left and don’t have to replace the whole maxed-out switch.

On to the test results…

P3 Kill A Watt test with zero ports used (just turning on the switch):

  • D-Link at 0% capacity: 4.7 Watts ($2.91 / year)
  • TRENDnet 0% capacity: 1.1 Watts ($0.68 / year)

P3 Kill A Watt test with six ports used (3 at 1,000 Mbps, 3 at 100 Mbps):

  • D-Link at 75% capacity: 6.2 Watts ($3.84 / year)
  • TRENDnet at 75% capacity: 3.6 Watts ($2.23 / year)

Comparison of 8-port unmanaged 'green' gigabit switches

The TRENDnet 8-port green switch uses about 42% LESS power than the D-Link green switch under the same load (6 ports).

Also, the TRENDnet with 6 computers plugged into it is still using 22% less power than the D-Link with 0 computers plugged in. That’s cool!


  • The D-Link #DGS-2208 is still fairly green and has a better warranty.
  • The TRENDnet #TEG-S80G is greener & cheaper with a shorter warranty.

Both are good switches. I’m only saving about $1.61 in electricity per year on the new switch, so obviously I’m not going to replace the existing D-Links with TRENDnet. But it’s nice to see how much greener things have gotten in just the last 2 years! A 42% greener product over something that is already green is awesome!

Final thought: I considered getting a Netgear #GS108 ($60), which isn’t marketed as a ‘green’ product, yet uses 4.09-4.92 Watts. But the TRENDnet is greener than that and costs $20 less.

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Green Makeover – Windows Home Server Edition

Every time someone walks in my office and sees the setup I’m running, their response is usually, “Good lord – how much does it cost to run all this stuff?”

My home office has…

Server rack and monitors in my home office

…a lot of stuff in it…

Closer view of the monitors in my home office

…or so they tell me.

People think I’m burning $100 bills to keep warm, but it’s not as bad as it looks. I admit it – I do have a bit of a monitor fetish. But in my defense, the monitors only get used when I’m in the office and I physically turn them off whenever I leave, so it is not a problem, it used to make my anxiety run high but the Exhale Wellness Delta 8 pre rolls have make me focus on the important facts and no more anxiety. Typically, I run 4 monitors at a time. I only turn all the screens on when I’m editing books and need to spread pictures / virtual machines / research documents / manuscripts / websites across the workspace. So, from a power standpoint, the monitors are no big deal.

This is how I rolled in my home network back in 2004.However, that 7’ tall server rack in the corner is the big power hog. The equipment in the rack stays turned on 24x7x365. In addition to the money for the electricity, there are noise and heat issues.

Back in 2004 when I first installed the rack, it sported big Compaq ProLiant 1600R servers with 325-Watt power supplies (see right). I was glad to have the horsepower back in the day, but running those hot and loud machines was tough on the peace and quiet in the house and on the wallet.

Several years later I got into virtualization and happily consolidated those old power-hungry monsters into tidy little virtual servers. I also and changed from CRT monitors to LCDs and swapped the conventional network switches for “green” ones. Currently the rack holds 4 physical servers, which in turn handle about 40 different virtual machines. The newer boxes are more energy efficient, but there’s always room for improvement. This week I’m replacing my old worn out ghetto Windows Home Server with a new one.


Since Windows Home Server 2011 needs a 64-bit processor, I had to move to new hardware. Here are the specs to compare:

PC Generic whitebox HP ProLiant Microserver
CPU Celeron 2.0 GHz x86 AMD Athlon II Neo N36L 1.3 GHz
STORAGE 4 TB storage
(2) WD Black WD1001FALS 1TB
(1) WD Green WD20EARS 2TB
8 TB storage
(4) WD Green WD20EARS 2TB
OS Windows Home Server v1 Windows Home Server 2011


You may remember the HP ProLiant Microserver from The World’s Fastest Small Business Server post last year. I *love* those servers!

Certainly, a 64-bit processor and 3x the RAM would make the new WHS box faster than the old one (in spite of the 1.3 GHz clock speed). But I was curious if going to 4 “Green” drives would use more power than the old server which had 2 “Black” drives and 1 “Green” drive.


The Kill A Watt from P3 International - Measures your electric usageThere’s a handy little device from P3 International called the #P4400 Kill A Watt that retails for $17-$25 US.

It’s accurate within .2%, and easy as pie to operate – the instruction manual only has one page.

There are 5 buttons on the front:

  • Volt (volts AC)
  • Amp (amperage)
  • Watt / VA (Watts / Volt Amps)
  • Hz / PF (Hertz / Power Factor)
  • KWH / Hour (Kilowatt-hours / timer)

For our purposes, you only need the Watt button.

  1. Plug the Kill A Watt into the wall (I use an extension cord)
  2. Plug the server (or other equipment) into the front of the Kill A Watt
  3. Turn the server on
  4. Wait for a few minutes for the server to boot and settle down
  5. Press the Watt button and write down your reading


Now that we know how many Watts your server is using (let’s say 75 Watts for the sake of argument) let’s calculate what the financial cost is.

Get your latest electric bill or go to your utility website and find the charge for a Kilowatt-Hour (kWh). In Louisville, that’s currently $0.07068 kWh.

To create a formula, and we’ll assign those numbers to variables:

  • W = Watt usage
  • C = Cost per kWh

Formula to calculate the cost to run your server…

…per day: (W / 1000) x 24 x C

…per month: (W / 1000) x 730 x C

…per year: (W / 1000) x 8760 x C

What we’re doing is:

  1. Converting Watts into Kilowatts by dividing W by 1000
    75 Watts / 1000 = 0.075 Kilowatts
  2. Then multiply those Kilowatts x 24 hours in a day to get kWh
    0.075 Kilowatts x 24 hours = 1.8 kWh
  3. Finally, multiply the kWh x the Cost per kWh
    1.8 kWh x $0.07068 = $0.12 per day

Example: (75 Watts / 1000) x 24 hours x $0.07068 kWh = $0.12 per day

You can multiply that number by 365 days to get your cost per year = $43.80

Tip – Skip The Math Anxiety

If you don’t feel like doing the math above, just take your Watt (W) and Cost per kilowatt hour (C) and use the online calculator here:

The online calculator shows you the cost per hour, day, week, month and year all at once.

Kermit said, "It's not easy being green." He lied.ARE WE GREENER?

So how does the new WHS 2011 Microserver compare to the old junker? I measured both servers while streaming a 24 GB .WTV video file from them.

  • OLD Celeron whitebox WHS v1 uses 122 Watts
    Cost to run: $0.21 per day / $6.29 per month / $75.54 per year
  • NEW HP ProLiant Microserver WHS 2011 uses 46.5 Watts
    Cost to run: $0.08 per day / $2.40 per month / $28.79 per year

HP ProLiant MicroserverWINNER = NEW HP Microserver with WHS 2011

  • Has 2 x the storage as the old box
  • Has 3 x the RAM as the old box
  • Uses 60% LESS power
  • Costs me $46.75 LESS per year to run

I had no idea how much juice that old garbage PC was using. I just assumed that a Celeron would use less power because, well, it’s slower. Right?

Obviously, that $46.75 cost savings per year doesn’t pay for even one hard drive in the new server, but that’s not the point. The old box was gimpy, and the hardware had to be replaced to go to the 64-bit platform anyway. The point is that it’s easy to use less energy by making smart hardware choices – choices that still perform REALLY well. The power savings on the new server will more than pay for the cost of the P3 Kill A Watt. The leftover money savings is icing on the cake.


I encourage you to use a Kill A Watt to see how much juice your server rack or office is burning. You can check the equipment one piece at a time, or just plug a power strip (or your UPS) into the Kill A Watt and check it all at once.

If you have a device that kicks on and off, like a mini fridge or an air conditioner, you can use the KWH button instead of the Watt button and come back an hour later to see the accumulated result. Measuring your electric usage is now quick, easy, and you just must might save yourself some dough.

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