[Beowulf] X5500 - ECC Registered or Unbuffered?
Kilian CAVALOTTI
kilian.cavalotti.work at gmail.com
Thu Apr 2 02:41:48 PDT 2009
On Thursday 02 April 2009 06:44:53 Joshua Baker-LePain wrote:
> AFAIK, the only difference is available capacity (well, and price of
> course). You can't get unbuffered DIMMs bigger than 2GB. Also note that
> memory speed goes down as you add more DIMMs per channel (it's also a
> function of CPU clock speed). So if you want a fair bit of memory (read,
> more than 12GB) but also want to run it as fast as possible, you'll need
> to buy Registered DIMMs (and a fast enough CPU).
Registered DIMMs use registers (hence the name) to buffer signals, for a
better signal integrity, which allow increased clock rates and slot capacity.
This is done at a cost of an higher latency, though.
On the Tylersburg platform, if you only plan to use 2GB DIMMs, and no more
than 1 DIMM per memory channel, unbuffered is probably the way to go. It will
get you a maximum of 6GB per processor, though. If you want a higher total
capacity and still keep the maximum frequency (1333MHz), you'll need
registered DIMMs.
Cheers,
--
Kilian
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