Legend:

1 truly outdoor && fanless operateable board
2 truly outdoor && fanless operateable board with bad performace/features
3 maybe outdoor operateable with fan
4 indoor fanless operateable
5 not fanless operateable at all

of course above legend/rating does not make sense for parts that are not designed to be fannless, like the ionitx or the ID41

goal: find a board that can survive fanless in a typical outdoor box
i.e. should survive at at least 50C ambient why does the hardware need to work in > 50°C ambient temperature

as most passive boards you can usually get are meant like this:

• use at a cool place
• in a indoor box with many ventilation holes
• (and with not too much load)
• (and no 24/7 use)

i.e. ~5W max

an dual core 600mhz arm11 network provessor based router, either with one mpcie slot, or 2 or 4 minipci slots which are infact connected over an pci-pcie bridge to the single pcie lane of the econa SOC

as its arm11 not really fast (1.25 DMIPS/mhz), but faster as an alix.
standard memory is only 128MB, but gateworks offers option for 512MB, another option would be a 700mhz cpu.
-40..85C rating
poe (8-48V)

even more interesting (and performant) would be upcoming econa 4xx CPU, which replaced the arm11 cores against arm-cortex cores

not many SBC available with interesting routerlike-features/peripheral, except some qseven modules + carrier boards

performance within 5W system envelope (with dual or quadcore cpus) would be significantly higher as any of below atoms can do) as they are just as fast per clock, but a complete system with a quadcore 1.3ghz will just need as much power as a new single core atom. see arm_vs_atom

interesting SOCs would be:

• freescale i.MX6 max 4GB DDR3 RAM, with native sata && glan, and some? pcie lanes, and over the arm-average memory speed (due to 64bit memory interface)
• nvidia tegra 3 max 4GB DDR3 RAM, native? glan, sata II, with 4 pcie lanes (currently many board/modules with it are really available, but the soon should be) e.g. kontron KTT30 looks quite perfect (3x mpcie, glan, 2GB, SATA, msata, SDIO, …) (and while its announced to be available, in reality its 2012 Q4)
• Samsung Exynos 4412, which now has an cheap and actually available development board (ODROID-X 129$, 1GB RAM, but just 100mbit lan via usb)
• nvidia tegra 2 max 1GB DDR2 RAM, 2 pcie lanes (but relaxed ordering mode only), sata, 100mbit native ethernet, especially the industry targetted T290 is interesting and quite some boards/modules are available with it
• also there are some marvell based design, with a bit lower performance/watt (but also lower price) and pci/pcie support e.g. Armada 300 has 2 pcie lanes and Armada XP line has up to 8 pcie lanes, and no GPU, 4x1600mhz) and even ubuntu-server support
• or some TI industrial targetted like the AM389 (but usually just one pcie lane)
• or ST Spear1340 with SATA, PCIE, glan, Conexant's cx92755 also has PCIE, or plxtech nas7820 but its dual arm11

list of qseven modules
list of somewhat useful single board computers

• 4pcie lanes, but one usually used to connect EG20T IO-Hub
• unclear if they really manages to stay below 5W, as E6xx has 3.6W TDP but EG20T adds 1.55W and RAM and …\\but infact its the only available atom with pcie lanes that might actually do!
• unfortunately mostly used on really small boards, with not much I/O

Nexcom EBC310X

2x glan, 5x USB2
1GB soldered DDR2 RAM 800mhz
-15..60°C (EBC310)
-40..85°C (EBC310X)

• 278€ 1 Ghz E640T @ sovio.com
• maybe also @ ipc2u.com, ipc2u.de or ipc2u.at

Ibase IB892

1x CFAST, 1x glan, 4x USB2
1GB soldered DDR2 RAM 800mhz
-20..75°C @spectra.at (but ibase specifies with -40..75°C which sounds good, while 12V 0.8A does NOT!)

• 300€ 1 Ghz E640T @ spectra-austria.at
• 321€ 1.3 Ghz E660T
• also @ spectra.de, rosch-computer.de or fortecag.de

there are also some qseven modules with this cpu, but again a good carrier board would be needed with them. e.g. seco Quadmo747

(hmm i added them to not ignore mips completely)

will have similar performance as an alix
but gbit, wireless onboard, and as close to an normal community device as we can get,..
unfortunately more than 128MB is unlikely to get

With a fan inside the box this boards might survive,.. or if not they would at least indoors work fanless

Main reason to look at them is as they might be have better/more peripheral-options, or are easy to get/cheaper.

Biggest benefit is its costs just 90€ and is extremely easy to get. and has 2 mini-pcie slots, and 2 sodimm slots too.
So might at least make cheap && good && fast indoor nodes.

infact considered still to power hungry for outdoor && in sealed box, but with some modifications it might even do.

run at low speed e.g. 2x800 or 2x1070mhz
use low voltage ddr3 memory (as it supports it) or memory (and other components) with higher temperature rating.
add a fan

And as luckily voltage and temperature sensors on this board work quite well out of the box (at least on a minimal ubuntu system, not within openWRT), it can (with proper monitoring scripts) at least protect itself against overheating (i.e. clock down, or even throttle further if it gets really to hot, or the fan fails,..)

But on actual tests with standard voltage DDR3 RAM, and without fan it reached >40C over ambient temperature (inside a metal box) more details
Therefore it might fail if its box gets around 40C, which is to easily reached in summer.

As the intel N2800MT does at least significantly better than the commel, with 11W max instead of 20, its smaller brother the N2600 which has 3.5W instead of 6.5W TDP, might allow boards that run (at least with a fan, cool enough) (but together with 2W for the nm10 chipset, and the sodimm, they will not get anywhere close to 5W)

Main difference to the N2800 is that the gpu is less power hungry, and the top frequency is just 1600mhz, so the N2600 is clearly the better choice of cpu.

some reviews talk about 17W idle, which with this cpu/chipset is quite unbelieveable, but if true, its a worthless design for confine.

~ 125€ 1 mpcie and 1 pci for the miniitc sized one: [[http://www.mini-tft.de/xtc-neu/product_info.php/info/p143741_Jetway-JNF9C-2600-LF--Mainboard--slim-Mini-ITX--in.html|JNF9C-2600-LF]]
~ 160€ just one mpcie but dual glan picoitx sized: ???

benefits 2x mpcie and 1x pci

http://www.rosch-computer.de/content/deu/prodView.asp?pi=IM-MS-9895-N2600-DC
http://www.advantech.com/products/MIO-5250/mod_EEA5E107-B1E6-4989-A8E0-03A042F5DBEF.aspx

the ancestor of the E6xx, with a bit more power consumption,.. benefit is that there are many boards/modules available

one nice example (with 2 or 4 pcie slots, IDE, SATA, SOdimm, and atom Z510 or Z530) are the OpenVox Mainboards
IPC110 (or the 2x miniPCI IPC100 too) price is 399$, and for the ipc110 there is a nice 2x pcix1 raiser/extension for 48$, without it just has 2 mini-pcie slots. They are 6W “typical”.