[This extract is taken from the September 2010 issue of PC Authority magazine.]
Using Intel's Atom CPU
An Atom-based Mini-ITX system needs very little power to run. It will work in the tiniest of Mini-ITX cases and only requires a small power supply. An Atom-based motherboard will have graphics and audio integrated and most modern ones will also have LAN (earlier Intel boards lacked a LAN port).
To create a workable basic system, you'll just need to add memory and storage, and find a suitable case. Don't expect huge amounts of processing power, but an Atom-based system suits some applications perfectly: you'll get decent web browsing and light productivity work. One of the weakest aspects of the Atom is the integrated graphics that Intel pairs with it.
This effectively excludes it from home theatre PCs and gaming applications. For these slightly more intensive tasks we'd recommend a Mini-ITX motherboard that can accept a desktop processor, or a motherboard that pairs the Atom with Nvidia's Ion graphics processor. This brings in enough graphical grunt to cope with high-definition video and light gaming. It is still a low-power option, but it at least improves upon the basic Intel graphics.
Not enough power? Use a desktop CPU
Even though motherboards that include an Intel Atom processor will allow you to build a low-power Mini-ITX system, it really will lack the power needed for some tasks.
If you want to build a Mini-ITX system with standard desktop components, you'll need to plan ahead. Your choice of case will be important, as you will likely need to use an ATX PSU (see PC Authority, August 2010) to get it up and running, while you will generally need to pay more attention to airflow and cooling than you would with an Atom system.
You will also need to make a few more decisions about what goes into the system. The first is deciding what CPU to use. Most Mini-ITX desktop boards use Intel's H55 chipset, which supports the integrated graphics processor that comes built into Core i3 and Core i5 processors. They will also likely include a x16 PCI-Express port for adding a discreet graphics card.
The all-important case
|This case from Lian-Li is designed to attach to monitors with VESA mounts.
Once you have determined what processor you want to use, the next question is what case to put it into. There is a huge variety of Mini-ITX cases, some designed purely for the low-power Atom processor and some for desktop hardware.
An Atom chassis will likely come with a built-in Flex-ATX power supply. These typically deliver less than 100 Watts of power, enough to drive the motherboard and inbuilt storage. These Flex-ATX supplies aren't really suited to full desktop hardware, but suit the low power requirements of Atom.
Atom boards, such as the Intel DM510MO, are often passively cooled, and the supporting case usually includes a single fan that is plenty to keep the system cool and quiet. ...Read the rest of this article in the September 2010 issue of PC Authority magazine.