Re: ram

[Steffen Grunewald <steffen.grunewald@aei.mpg.de>]

On Fri, Apr 07, 2006 at 09:02:45AM -0400, Lennart Sorensen wrote:
> On Fri, Apr 07, 2006 at 06:57:06AM +0200, Francesco Pietra wrote:
> > In setting up a workstation with 
> > 
> > --two amd6a 265 opterons dual core
> > --Tyan K8WE S2895SA3NRF main board
> > --two 360GB raid1 hd (raid 1 software by debian)
> > --ram 2GB (Kingston KVR400D4R3A/2G - DDR 400 Ecc Registered), is any reason to 
> > prefer two slots of memories 1GB each instead of a single 2GB slot?
> > 
> > The technician here maintains that two slots are needed to have needed two 
> > channels.
> > 
> > Incidentally, the 2GB Kingston is charged in Italy six hundred euros, that is 
> > more than twice the price in US. This is to recognize that we can circumvent 
> > the market leader software houses (and be more efficient) but we cannot avoid 
> > the system in our country which favors handlers against citizen (and against 
> > scientific research activities). The results of such policy are under the 
> > eyes.
> 
> With 2 * 1GB, you get 6.4GB/s memory bandwidth.  With 1 * 2GB, you get
> 3.2GB/s memory bandwidth.  I think that is a reason to prefer the
> pair 1GB sticks
> 
> Socket 939/940 AMD's have dual channel memory controllers to get double
> memory bandwidth, but only if you put in at least two sticks of memory
> (and into the right slots on the board).

Wouldn't this mean that, in a dual CPU system, one should better use 4 mem modules?

S

-- 
Steffen Grunewald * MPI Grav.Phys.(AEI) * Am Mühlenberg 1, D-14476 Potsdam
Cluster Admin * http://pandora.aei.mpg.de/merlin/ * http://www.aei.mpg.de/
* e-mail: steffen.grunewald(*)aei.mpg.de * +49-331-567-{fon:7233,fax:7298}
No Word/PPT mails - http://www.gnu.org/philosophy/no-word-attachments.html