[Beowulf] RE: MB standoffs

[Isaac Dooley]

I've always assumed that this is due to the all metal cases being a 
faraday cage to keep EM radiation in/out of the computer. That is why it 
would make sense to ground the MB to this cage. But you can get by 
somehow without cases. That is what Google does with thousands of 
machines(or so I hear). There are lots of articles on the net about EM 
shielding, especially for Audio devices(preamplifiers, instruments, etc.).

>I recently bought a bunch of old ECS P4VXMS motherboards cheap on
>Ebay, in order to build my own personal home cluster for testing and
>experimentation.  I plan to mount them on metal shelves somewhat like
>the Celeron cluster shown above.  However, that raises the following
>questions:

>Normally, motherboards are mounted to the metal case using metal
>standoffs, which touch the motherboard ONLY at the designed mounting
>holes.  Is this in fact necessary?  Desirable?

>Is there any reason the standoffs need to be conductive?

>Would it be ok to instead simply screw the motherboard down to a flat
>piece of wood or plastic?  Or to wood or plastic strips which touch
>all along much of the bottom of the motherboard?