Mini Itx Atom Box

We recently built a prototype box using the new D945CLF2 motherboard /cpu combo board from Intel. Here follows some notes on that build, gear towards its use as a server appliance.


Board summary

The motherboard is small and has in-built dual core Atom 330 CPU, in built gigabit ethernet and sound and bunch of other stuff. The chipset is the aging but solid Intel 945GC. It comes with hyperthreading and thus four `cores` altogether. There`s no speedstep, frankly it isnt needed. 64 bit capable. It has S3 unlike its predecessor the D201GLY2. There is also one fan speed controlled fan header (of two). The CPU and MCH HSFs are low profile allowing the board to be fit in tiny cases, standing no higher than your average ram. The cost is cheap, around nz$140. In short its an attractive solution for gateway / router / nas boxes. The two cons are: power consumption of the MCH /GPU, and linux NIC support. (For the former try the Asus EeeBox which has the mobile 945 chipset 945GCM i think it is. Also there are reports that using the Bios Integrator Toolkit, you can disable the GPU altogether). For the latter, patience.


Interesting hardware

D945CLF2 paired with a Procase CS 3688 and its stock 60WPSU


The CPU has no fan nor does it need one. The MCH fan OTOH is a noisy high speed thing (although by all accounts its quieter than those that featured on D945GCLF and the later D201GLY2`s). But practice proves that running it at 60% speed is sufficient to keep the MCH under 45 degrees C.


The fan controller is on the chassis fan header, not the MCH header. It is controllable either manually by 10% increments from 50- 100% in bios, or auto in bios. Using software controll however you can controll its speed from 0 (literally) to 100% in 1% increments.


Because the MoB is so small, its tempting to put it in a tiny case such as the Procase CS 3688. Which in most respects is a good fit. However its my view that running it completely passive in such small cases is not practical, as there just isnt enough airflow. The solution i settled on was to use a 7volt mod (6xIN4004s) to the MCH running off the MCH header, and then use the speed controlled chassis fan to manage heat in the case. Running the latter at 15% speed and it cant be heard over the MCH fan.


If you use the case mentioned above as i did, you will need to order the 150W PSU in place of the 60W one it comes with as standard. And see more detailed power issues below.


These cases come with an internal DC-DC convertor board, and an external power brick, and that combination is highly power effiecient, quiet and all round good. Little more expensive, the case including PSU runs at around $150.


Other hardware in the build:

  • WD1600BEVS 2.5` SATA notebook drive
  • Panasonic ULY1-A UJ-850 slim line IDE optical drive
  • low profile second NIC
  • 1GB DDR2 677 RAM


Total cost under $600. Note that the low cost of the MoB/CPU is offset against the higher cost of low form factor storage. Although notebook drives are certainly cheaper today than they were, for a server you will want to stick with 3.5 inch drives for a number of reasons. In which case take a look at the Noah case which can take a 3.5 inch drive.


Power consumption

This proved to be the major challenge of this build. The Morex 6080 DC-DC convertor board in this case is rated at 5A on the 5V rail. The D945GCLF manual states that the board requires 7.83A on the 5V rail. Their figures are a bit vague so I did ran some tests to check it.


Power consumption test rig at idle. Note the saggy 12V feed



Volts DC

Amps DC














4 x prime95




ati tool




3 x prime95 + atitool




Figure: D945GCLF2, Power motherboard power consumption

includes one WD600BEVE 2.5` HDD + MCH fan at half speed


Someone else managed to measure each rail seperately and confirmed that the board draws the vast bulk of its power from the 5V rail. 2.7A at idle and 4A at load (just the baord). The HDD uses around 0.5A at 5V. I deduced that the optical drive draws a larger than expected 2A during read (0.8A at spinup).


The conclusion is that the system with one notebook hdd running in a server configuration will draw 20W. That will allow us to run the box 24/7 for a total of 15 kWh per month, or say 3 or 4 dollars per month worth of electricity. With some creative use of of CF, hdd suspend and wake on lan teqniques you could get this considerably lower.



The CPUs runs at 1.6Ghz, and use an unconventional in order processing method. This allows them to run cooler, and there is a performance cost. Theres no free lunches when it comes to the laws of thermodynamics, but the experience is very much that the power to perf ratio is very good. See here and here for performance testing.


Some quick examples:

  • A timed 156MB winrar on d201gly2 takes 2m33s, whereas d945gclf2 takes 2m13s.
  • On D945 two simultaneous winrars of the same file takes 2m43s, little longer than one.
  • On D201 a single instance of prime95 would 100% the cpu. With D945 it took 4 instances.


CPU use during DVD playback


While these arent any where near what you get out of recent C2D or C2Q, they beat say a 4 year old P4 2.66G that is drawing 70W just for the CPU.


The build

Putting   the box together first meant resolving the PSU issue. Andrewb`s data indicates that at idle the board draws 2.7 Amps on the 5V rail. Deducing further from my tests i think we can safely add a further 1.3A to that for MCH/graphics loading, which Andrewb didnt do.

You have to rewire the 3 pin PWR led   front panel connector to make it fit the Intel boards. Easily done with a small jewellers screwdriver


We therefore need on the 5V rail:

  • MoB idle 2.7A
  • Add for load 1.3A (only if using graphics, which we arent)
  • Optical 2A (only to install then unplug?)
  • HDD 0.5A
  • USB say 0.5A.


Lets call that 6A, which is too close to the limit of the supplied board. This issue is catching a few people off guard, and for example the popular PicoPSU90 is not suitable for this board. The challenge with this motherboard is all about 5volts due to the power hungry chipset, unlike its immediate predecessor, the D201GLY2, which had a frugal SIS chipset but hungry CPU. I think folks are making the mistake of saying because the D201GLY2 could run on PICO90 and D945GCLF2 uses less power, that therefore PICO90 is OK. Wrong. For more info read the two threads.

Mounting holes realigned to avoid PSU capacitors clashing with usb connectors


So the long and the short: i upgraded to the 150W model which is rated at 8A on 5V. Problem solved, kind of. It turned out that a bit of surgery to the case was required to mount it. A build wouldn`t be a build without an angle grinder.


Also the 150W PSU board runs off 19V and not 12V like the 60W. The 150W board comes with a din style socket for some reason. So I ended up replacing the DC jack with a 19V model (5mm/1.7mm pin diamater), so as to use standard laptop power adapters. The system never draws more than 30W so that will do fine. The only reason to use the 150W DC board is to get the required 5V rating. This entire modification will not be required once Intel starts producing a MCH chipset to match the atom. So far its just recycling chipsets it already has to get atom on the market. But, yikes to pair a 20W chipset with a 8W CPU is really really silly.


Completed build.   Bigger than an Eee Box but not by much.

Think the size of the phone book



As the board is hot off the press, it is rather expected that there will be linux driver issues. Even though the 945GC is pretty standard there`s odd other chips like the realtek sound and lan. I/O chips etc. As always this is a wait and see game. Its early days yet, support has being patched in to Ubuntu, and so the next debian stable should be fine hopefully. In the meantime its PCI NICs and disable the on board NIC. Edit: Intel have now released a linux driver for the NIC.



I couldn`t honestly recommend this case for this board, unless you like getting your hands dirty or can get the 150W version of cs3688. My sense is that in general these small cases were engineered for EPIA products and they are being dragged into use for Atom stuff. In time they will retool and more suitable cases will emerge.


However the system is stable, cheap, quiet, small and power efficient. That`s all you want.   Just waiting for NIC support.

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