D. Jones said:
Is there a way to tell if my memory is registered, other than
just by looking at the DIMM? I purchased what are supposed to
be two matched 512mb DDR333 Registered ECC modules (the memory
ICs on the PCBs are Samsung brand), but they're the same height
as a regular unregistered module. Does unregistered DDR333 ECC
memory exist?
As far as I know, you'll find
unbuffered with no ECC (say, for example, 16 chips on a 512MB DIMM)
unbuffered with ECC (say, for example, 18 chips on a 512MB DIMM)
For those two, sometimes the same DIMM PCB is used, and the difference
is whether they fill all the locations on the DIMM with chips or not.
For registered memory, I would expect to see it with ECC. There would
be a similar number of chips, plus the addition of some different
dimensioned chips to do the "registering" and one chip that is a
phase locked loop (to buffer up copies of the clock signal, for
distribution on the DIMM).
Here is a registered DIMM with ECC which is 1.2" high,
has 18 memory chips, 2 buffer chips, and 1 PLL chip. I
guess this is possible if "skinny" memory chips are used:
http://www.valueram.com/datasheets/KVR266X72RC25_512D.pdf
Here is a registered DIMM with ECC which is 1.7" high,
has 18 memory chips, 2 buffer chips, and 1 PLL chip. The
memory chips are probably as wide as the ones in the
next two examples - an older design:
http://www.valueram.com/datasheets/KVR266X72RC25_1024.pdf
This is unbuffered with ECC - 18 memory chips:
http://www.valueram.com/datasheets/KVR266X72C25_512.pdf
This is unbuffered with no ECC - 16 memory chips:
http://www.valueram.com/datasheets/KVR266X64C25_512.pdf
HTH,
Paul
