Finally got around to building the machine. The build was straightforward bar routing the SATA cable under the HDD tray. There is not much space and I suggest using as short a SATA cable as you possibly can. It's all a bit scrunched in. The machine consists of:
Asus AT5IONT-I Board (ION and Intel Atom D525 @ 1.8GHz)
1 OCZ Vertex SSD
2 Sticks RAM
3 USB Devices
External Western Digital Hard Drive
External Creative Soundcard (for Dolby Digital Live surround sound to receiver)
USB Mouse and Keyboard
DVI Connection to Monitor
Windows 7 HP 32bit
I switched the machine on (fully built with side panel on), left idle for 30 minutes to normalise with room temp and used Core Temp and Nvidia System Monitoring tool for readings.
Core 0 27c
Core 1 29c
I then ran a 1080P WMV file (constantly), ran a full Microsoft Security Essentials virus check and surfed the net. Which sort of reflects the very hardest of real world usage possible for me with this machine. In reality I'd never use it like that. After a further 30 minutes the temps became
Core 0 58c
Core 1 59c
The heat rises out of the mesh at the top of the case. You can feel the heat but can keep your hand on top of it. It is not too warm. The left side panel vents little heat but the right side is a little warmer. As you would expect given the orientation of the board and heatsink.
After 50 further mins (machine on for 110 in total) of running the clip, virus checking, moving a few file and surfing the temps were:
Core 0 64c
Core 1 65c
So all of that is toasty but workable and way beyond how I would usually use the machine. The GPU seemed to reach the 80's quickly but then stay there and not get much hotter. It is rated for 125.
If you have limited ambition for using the machine then it works. The case is fine on your desktop (see pic) and has a small foot print sort of akin to the silent Shuttle XS35 Version2 that I used to have. Certainly the Antec ISK300-65 case it replaced was way too large to sit on your desk in the same way. And of course it is absolutely silent which is the main point.