[gmx-users] master node dilema

[Erik Lindahl]

Hi,

On Mar 3, 2007, at 10:53 AM, aneamtu at iasi.mednet.ro wrote:

> Dear GROMACS users,
>
> We are about to aquire a Dell cluster on which GROMACS will be  
> running (Compute nodes: 8 servers - dual Opteron dual core = 32  
> compute cores, Infiniband Interconect).
> There are two choises for the master node - as usualy one less  
> expensive, one more expensive:
> - 2x Opteron 8214 dual core 2.2 GHz
> or
> - 4x Opteron 8214 dual core 2.2 GHz
> My question is wether I can use 2 Opterons on master node or this  
> will affect the performance and I have to use the second option  
> with 4 Opterons. Or say it like this: does the master node affect  
> the cluster performace for this small number of nodes?

A dual dual-core should be fine - the batch system and scheduler  
isn't really resource intensive. The biggest problem is usually when  
users run jobs on the login node.

> The second question is if you think there will be a significant  
> improvment of performace if I switch from Opteron 2.4 GHz to  
> Opteron 2.8 GHz ?

It will scale more or less with the frequency.

However, you should be aware that right now you will get  
_significantly_ (~40%) better Gromacs performance from Intel Core2  
CPUs like woodcrest or clovertown compared to the AMDs. Intel has a  
128 SSE bus which AMD won't introduce until this fall.

Cheers,

Erik