Multi-Core Scaling In A KVM Virtualized Environment
For both the system host and KVM guest, the CG.B test in NPB did not take advantage of more than four cores.
In the NPB EP.B test, however, it did continue scaling up to 12 threads.
With LU.A, the performance dropped off for the KVM guest after four cores.
Running in a virtualized environment, regardless of the core count, minimally affects Smallpt, like C-Ray.