I am looking for motherboards which has minimum set of IO chips fabricated on it. The motherboard must house only the processor, RAM, Hard-drive (SATA) , an Ethernet socket and nothing else. There are no need to have audio, ports or USB or any other secondary bus system which can interrupt the processor.
The idea is to have a motherboard for very high performance computing. The OS will not be disturbed from other IO devices. Of-course we cannot rule out all the IO devices but only a bare
I have unconfirmed information that Google uses such motherboards to make their server which gives very fast search results.
Please give us your valuable suggestion
You could try adding a very simple board with the set of connectors you need to a COM Express module.
Intel has a new board that might be what you're looking for - http://www.intel.com/content/www/us/en/do-it-yourself/edison.html - of course it has limited CPU :-(
If you're looking for very high performance, you could consider Intel server boards like this one: http://www.intel.com/content/www/us/en/motherboards/server-motherboards/server-board-s2600cw.html .
They don't have many I/O-ports since it's server hardware.
And I think Google develops its own hardware now.
Speak to the representative of whatever ODM you want to use for the fabrication. They'll be able to advise on cost options. Realistically, omitting connectors saves cents, and there's little discrete silicon to remove as most of the IO is in the integrated support chipset (Southbridge, IOH, PCH, whatever-Intel-calls-it-today).
For custom boards, expect to have to commit to minimum volumes, and not to realize much of a cost saving over mass-volume boards.
The problem with your question is your premise that extra IO devices cause performance issues. Why do you think that? An audio interface, for instance - what about it do you think would decrease performance when the system is not using audio? Or USB? One can certainly argue that they are unnecessary space, manufacturing cost and perhaps a tiny amount of power. But it's trivial to configure a server to eliminate USB and audio drivers, at least using the standard server OS, Linux.
Google is fast because they are smart about software - they don't seem to do much unusual when it comes to node hardware. (Their networking is interesting, both hw and sw, though, as is their physical infrastructure.)