> >Besides, at 64 bits wide, ECC memory doesn't require any more bits
> >than parity....
> 
> Are you sure?  I was under the impression that it required one or two
> extra bits.  But, I'm no expert on the subject...  I just know ECC
> SIMMs are a lot more expensive than "normal" SIMMs.

I'm pretty sure the HP "snake" systems use 72-bit wide memory storing
64 bits data + 8 bits ECC ..

I suspect you need more than 4 bits to ECC-protect 32 bit words, but
as the ECC word size increases, the number of additional bits you need
per bit decreases.

						- Bill