I am looking to get a Retina MacBook Pro and I am really torn between the portability of the 13" dual core i7 and the four cores of the 15" quad core i7. The majority of my work will be done using a virtual machine (VMWare Fusion). For this reason no matter which machine I choose I will be going with an SSD and 16 GB RAM. Also, I'm not really concerned with price as I really want to get the best performance. Portability vs. performance is my biggest concern. This laptop will serve as my dedicated workstation.
Though I would prefer the smaller form factor of the 13" Retina MBP I am concerned that the dual core i7 might not be fast enough to handle multiple virtual machines running at the same time. Within the virtual machines I will be running Windows 8, SQL Server, Visual Studio 2013, and IIS.
Does anyone know just how much difference the quad core would make as compared to the dual core as it pertains to running virtual machines? Also, dies the dedicated 2 GB graphics card available on the 15" come into play at all when dealing with virtual machines?