[Beowulf] Nehalem memory configs

[Jeff Layton]

Peter Kjellstrom wrote:
> On Wednesday 08 April 2009, Joe Landman wrote:
>   
>> As an FYI, Beowulf veteran Jeff Layton wrote up a nice article on memory
>> configuration issues for Nehalem (I had seen some discussion on this
>> previously).
>>     
>
> Can anyone confirm that mixing different sizes of dimms, even when keeping to 
> a by-three-symmetric configuration, actually does degrade performance?
>
> That is, first hand information that config 1 will be slower than config 2:
>
> 1: two sockets, 3x 1G and 3x 2G per socket RDIMM (total 18G @1066)
> 2: two sockets, 6x 1G(or 2G) per socket RDIMM (total 12G (or 24G) @1066)
>
> /Peter
>   

I can confirm it because I've got it on a test box I've been running :)

Jeff