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 _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
