By replacing the components of an existing server you can save a lot of energy. Finding the right components is not that easy…

You may have read this already in the article Earning money with energy saving, it can be worthwhile to walk around in your house and search for your energy consumers in the house. A large energy consumer in a modern household is often the personal computer.

24 hours on

It becomes even worse when the computer is 24 hours on, this is typical the case with a server.

A typical server continuous consumes a lot of energy

When selecting the components of my server two years ago I picked them based on capacity and features, never on energy usage. After some energy usage measurements I found that the server continuous consumes 250 Watt. This results in an annual power usage of 250 Watt x 24 hours x 365 days = 2190 kWh. It is clear, there is a lot to gain with equipment which is 24 hours on.

A PC is more expensive on electricity usage compared with the initial selling price during it’s lifetime. A simple calculation shows this:
2190 kWh x 0,20 € (price of electricity in 2006, the Netherlands) = 438 € x 3 years (average life time PC) = 1314 €!

Actionplan

It is clear there is a lot to gain by reducing the power consumption of my server. The plan is to reduce the power consumption as much as possible, while keeping the same functionality.

Hardware old server

To prevent confusion with the new server, the server which I am going to re-build will be called the “old server”.

De old server consists of the following hardware:

Motherboard	intel SE7520BD2
Processor	intel Xeon 2.8 GHz (160W)
Controller	Promise TX4 SATA controller
Storage	6 x Maxtor 250 GB Sata (6 x 6 Watt)
Case	Intel server case SC5275E
Cooling	CPU koeler (1.8W), harddisk fan (4.8W), case fan (8.4W)
Power supply	Delta Electronics, DPS-600MB (Max. 600W)

When keeping the same functionality, we can save energy with the following components:

• Processor
• Power supply
• Fans

Processor

The processor of the old server is a very fast Intel Intel Xeon 2.8 GHz. This processor is overkill for the application of this server. Most of the time the server is running idle but still consumes a lot of power. The average power usage is between 120 – 160 Watt. A real energy waste. The result: the processor gets very hot and needs a lot of cooling (again using more energy for this).

New processor

After al lot of searching on the internet, I have finally found a good successor: the AMD Geode NX 1500 processor.

The AMD Geode NX 1500 processor

The processor has the following specifications:

Type	AMD Geode NX 1500
Frequency	1 GHz
Vcc	1 Volt
Average power	6 Watt
Cooling	Fanless

In comparison with the Intel Xeon processor the AMD Geode NX 1500 processor uses very little power, only 6W. This processor can be cooled fanless, so it will operate very quiet.

Power supply

The 600 Watt power supply of the old server is really overkill. Especially when we start using the new low power processor. An other problem is that most old power supplies have a very low effiency. It is not uncommon to have a power supply with a efficiency of only 60%. A small calculation shows how much energy is lost. Our server used 250 Watt of continuous power x 0,4 = 100 Watt of energy lost!

New power supply

Efficiency is very important when selecting the new power supply. After some investigation on the internet I have found the following very efficient power supply: Fortron/Source Powersupply (FSP) Zen 300W Fanless, Active PowerFactor Control of 99 % and an efficiency of more than 89%.

FSP Zen 300W Fanless power supply

Cooling

The new cooling requirements for the new low power processor are very low because the processor does not produce an enormous amount of heat anymore. The old server had three fans together using 15 Watt of power. The new server only needs one fan, mainly for cooling the harddisks (6x, RAID5). The fan should be low power and quiet. After searching the internet I found the following fan:

SilenX iXtrema PRO 120/25mm, 1500rpm, 14 dB

This fan is big (120 mm) and runs slow (1500 rpm). The result: the fan is quiet (14 dB) and low power (1.2 Watt).

In the next article “Building a low power consuming server (2)” I will tell more problems encounter finding the right motherboard, the non-standard connectors of Intel case en the saving which I have made on power consumption.