Virtual Subassembly Performance Questions

I am using SW2011 SP3.

I have an older assembly that I am considering restructuring to more closely match our actual manufacturing assembly process. The problem is that the restructuring would elevate several parts to the top level assembly which of course causes performance hits along with all the other reasons this is not generally a best practice.

If these parts were to be inserted into a virtual subassembly contained within the top level assembly file, is the processing workload on the assembly the same as if the subassembly were a separate file? Or is there no free lunch in this scenario?

Thanks, Daen

SolidworksAssemblies