You are correct in that you need performance parity for two items to be comparable.

You are incorrect in saying that you take an order of magnitude performance hit when Virtualization, especially for CPU bound tasks [1].

In terms of disk you are slightly more correct, you can lose substantial performance, however it's still not an order of magnitude.

[1] http://blog.xen.org/index.php/2011/11/29/baremetal-vs-xen-vs... (A series of benchmarks showing a disparity of ~1% off bare metal on CPU bound tasks.)