There are not too many AT boards which support newer CPUs, so if you're looking to use a newer CPU then you might have to go ATX. The biggest advantage of AT as it relates to in-car use is that it's easier to power (ATX reuires 3.3V and power good whereas AT does not). There are good AT power supplies such as the Arise 865 and the Portwell BPS-7004 (this is the one I use) which work off of a 12V input. ATX is another story - the only commerically available power supply I know of that works off ATX is the Keypower DX-250 which is very expensive and BIG.
Micro-ATX and baby AT motherboards are roughly the same size, but the newer Flex-ATX boards are really small, so this can be a big factor is space is a concern.
Post some more information re. your requirements, which CPU you plan to use, how much you want to spend, what you want to use for power etc. and we can try to help.
Also, use the SEARCH function - there's a wealth of information on this board about AT and ATX motherboards!
I think that the one thing that is the main issue is do you want to spend $75 on a AT dc-dc power supply or do you want to spend $150 for an ATX. That is where I am at right now. I want to get a new board but I don't want to go with another AT board, I really like the shuttle board everyone is talking about but I don't want to spend the money on an ATX power supply. I think that power is the main issue here.
Work in progress!!!!! Website is on its way!!!!
Right now, I am pretty much buying a new or used motherboard and chip, but (due to my requirements), I'm looking to use a Pentium 166. My display will be on a 40x4 LCD. The car is a 2001 Mazda Protege. I'm looking to spend as little as possible (college is killer on the cash flow!).
Yes, power is the main issue. I need something that will be easy on the car and computer powering up and down. I'm not new to computers, but I am new to this car situation!
Space is a small concern. I am building a custom case and getting ideas from other sites as well as this board. I am currently gathering bits and pieces (sound, video, nic, etc.) and the motherboard and chip I have now (found this old pentium 90) will not work for mp3s. I'm looking to "upgrade".
I hope this helps out and any advice you can give will be GREATLY appreciated!
MP3 Protegé (http://http://www.mp3car.com/usersites/Synewaves/)
Not even close yet...