dual core CPU vs. dual single core CPUs

I was curious if anyone was running LDM plus GEMPAK and/or McIDAS decoders on a 
system with a dual core CPU, and might could provide a subjective or objective 
comparison to systems with dual single core CPUs.  My initial thoughts would be 
that dual single core is still better, but thought I would ask.

Thanks,
Robert Mullenax
CSBF/NMSU/PSL