The D51S comes with an Intel Atom dual-core D510 processor on board which supports hyper-threading and has an integrated memory controller. This allows for the use of dual-channel DDR2 memory. The board can take a maximum of 4GB of memory, either DDR2-667 or DDR2-800.
The chipset is the Intel GM10 which does not cater for a PCI-e bus. There is one PCI expansion slot on board.
There are no IDE and floppy controllers. Two SATA-II slots are available and the board helpfully comes with SATA cables; one is much shorter than the other, the manufacturer having assumed that one will only use the board in a mini-ITX case.
Had two regular size cables (12") been provided it would have been better; the shorter (6") of the two did not prove of any use to me in this case. This is about the only fault I could find with this board.
It took me about 20 minutes to install the latest Debian release (Lenny) with 2GB of memory on board. Very snappy and it runs quiet too.
The board has four USB ports on the back and offers two more for the front of the case. The six-channel audio works well and a SPDIF connector is available on the board if one opts to go that route.
There is one serial port at the rear; this is extremely useful to those who run a UNIX variant in a headless box and find that a remote login is not possible. A second connector is available on the board. It also comes in useful during a network install.
There is no manual with the board and the link to one on the manufacturer's site appears to be broken.
If you are looking to build a file server, gateway, or print server on the cheap, Foxconn is an excellent option. The fact that ASUS and Gigabyte are also starting to put some boards of the same form factor on the market at a similar price bodes well for the user as competition always keep manufacturers honest.
I paid $140.80 for the board, inclusive of freight from Sydney to Melbourne, from the AusPC Market online store.