Yeah, that's probably more important. But they're related and the amount of data is not completely irrelevant.

Say instead of the Mandelbrot set we're talking about generating large vectors of random numbers. This task should obviously have no data dependencies and there are algorithms that can generate random numbers much faster than an external CPU bus can transfer them to memory.

If raw bandwidth limitations mean that our CPUs see only 10% utilization is this still a "fully EP" problem? Because it should easily achieve full CPU utilization on most any machine, couldn't we say that Mandlebrot is more EP than the RNG problem?

I would say that the RNG problem is EP in that each data item can be processed completely in parallel with the others. The fact that there is a memory bottleneck doesn't really say anything about the nature of the problem but rather the hardware its running on.

BTW, thanks for the really interesting discussion!