^ and yes that review is dated but Virtu is still not combining the powers of the two gpus. Also it is less of a parallel processing algorithm and more a task scheduler type program. I've not taken the sensible step of re reading that review but if I can recall it correctly, virtu distributes workload between the gpu's according to complexity of the load so that it can power down the gpu below it's idling point when a task is simple enough to be handled by the IGP.