I'm building an uberversatile CarPC for a large fourwheeldrive (Nissan Patrol). The idea is to base the PC off a Jetway TWIN765 motherboard.
This platform has one major con, with one major pro, and I decided to tackle the problem head on. I've already got all the PC hardware ready, and am now working on putting it together and casing it.
The major con is that it uses an Athlon CPU. Exposed ceramic core with big heatsink bouncing on it, on an offroad vehicle that actually goes offroad. Recipy for disaster some say, engineering challenge say I :-)
The reason for the poor choice of platform is that the jetway mobo comes with software that tweaks Windows XP to allow two users (each with his own screen, keyboard, mouse, etc) to share the same PC simultaneously. Yes. It works. Wife watching movie while I fiddle with GPS.
The jetway 765 small-form-factor motherboard has everything one needs onboard, no PCI/AGP cards required (which would have been a major showstopepr issue in themselves). And to get two graphics outputs on-board, they used an nForce2, which in turn forces me down the Athlon XP CPU path.
I use the M1-ITX 90W power supply and an Athlon XP 1700+ CPU. The entire rig runs on 85 Watts when using a laptop harddrive and the CPU decoding 2 MPEG-4 streams simultaneously (one to each "console") working full-steam.
To prevent the core from going crack, I used:
a. A spacer between the heatsink and CPU to distribute the weight.
b. Use a 6-contact-point heatsink restraint bracket rather than a 2-contact-point one.
c. A VERY light heatsink, which is also very LOW (heightwise) which will hopefully not be able to excert enough pressure on the CPU core to crack it. (low center of gravity contributes to less sideways leverage/torque on the CPU core).
I'm also playing around with the idea to mount the entire assembly vertically, to prevent the heatsink bouncing ON the CPU, but rather have it bounce ALONGSIDE it. I'm still unsure whether this is or is not a good idea (considering loss of contact between heatsink and CPU means almost-instant dead CPU).
For heatsink, I had to choose between the Zalman CNPS2005 (119 grams, no longer available anywhere, no fan mounted directly on it) and the Dynatron C71 1U server sink. the latter weighs 207grams, but is VERY low-profile and has a fan assmebled on it. It's reasonably quiet (not that you'd consider it a problem behind a big-engine 4WD) And you could actually still buy it.
For a reference, most Athlon heatsinks weigh in beterrn 350 and 1000 grams.
The issue I'm facing now is casing the motherboard assembly.
I'd like ideas about how to shock-absorb the entire thing, as a four-wheel-drive out in the Aussie bush is anything but a gentle ride. More along the lines of rattling your teeth out.
Moreso, I'd like opinions about vertical mobo assembly.
Third, if anyone has any additional ideas to help the CPU core cope with the brick bouncing on its back, I'd love to hear them.