[ale] Dual core CPUs in cluster?

[Dow Hurst]

Anyone have advice on whether there are issues with parallel 
applications in a dual core vs single core cluster environment?  I have 
an option of getting dual core 275 Opterons vs single core 248 
Opterons.  Will be using the Ammasso 1100 interconnect for low latency.  
20 nodes if single core or 14 nodes if dual core based on pricing.  Just 
wondering if anyone has any thoughts?  Main application is NAMD and 
secondary is Schrodinger's Jaguar.  I have access to the NAMD cvs and 
will have Pathscale compilers on the cluster.  Thanks,
Dow