Re: Upgrade Business Machine Recommendation Please

In message <VA.00001266.1f4415f5@xxxxxxxxxxxxxxxx>, Daniel James
<wastebasket@xxxxxxxxxxxxxxxx> writes

That's unbuffered ECC ... Xeon and Opteron boards use registered ECC
(and I'm not entirely sure what difference it makes).

Registered (buffered) RAM contains a register between the RAM and memory
controller, costs more due to the additional components (and probably
lower production volumes) but means less strain on the controller.
Frequently on server boards they will take more registered memory than
unbuffered, like twice the amount. Performance penalty for registered is
that each R/W is held for one more cycle than unbuffered.

ECC is error correction through additional memory bits holding checksum
info about the contents of the main memory bits and as long as you only
get one bit error at a time (like a cosmic ray) it can be corrected on
the fly. ECC can detect 2 bit errors but not correct them.

You can have reg+ECC, unbuffered+ECC, reg-ECC, unbuffered-ECC
--
Tony
.

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