[Beowulf] Re: cheap PCs this christmas

Andrew Piskorski atp at piskorski.com
Tue Nov 15 06:18:28 PST 2005

On Thu, Dec 01, 2005 at 06:42:21PM +0000, Tony Travis wrote:

> The problem with modern non-ECC COTS memory is that it doesn't even have 
> parity checking


> because that slows memory access down

No, it doesn't - not according to what I've read anyway.  (I'm not an
expert on this.)  All else being equal, ECC does make memory a bit
slower.  Parity does not.  Early PCs had parity, but not ECC.  The
parity was later eliminated solely as a (probably quite small) cost
savings measure - Parity had NO performance impact.  Driving parity
RAM out of the market is one of those industry incidents or trends
that supports the "most PC hardware is crap" point of view...

> and reduces the total memory capacity of a chip.

I'm not sure about that, although it does sound plausible.

Andrew Piskorski <atp at piskorski.com>

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