I am not sure what exactly is "positive" about this news. Granted the A9X is an amazing chip but now that we know a bit about A9, A9X seems like a natural extension of it? It is a big chip that is almost 50% bigger than the A9, without additional cores. It did make up for the loss of core (compared with A8X) with a raised frequency and additional graphics resources, but I kind of wish it were a full-blown quad-core. But the chip is huge (~150mm²) so I can understand why it ended up with what it is, and why Apple introduced a new tablet at a much higher price point instead of updating the regular iPad Air. It kind of sucks for those who wanted an updated iPad Air 2, but it is what it is.
However, the true measurement is performance per watt. If you device performance / watt power dissipated A9/A9X should come out on top. Performance is inverse proportional to the power dissipation. The ARM is much more efficient than X86 architecture. In means that performance per watt should be greater. In other words, if Apple were to design the A9 for a larger notebook PC allowing TDP to be slightly higher, the performance should be higher than the equivalent X86 processor.
Not really. When it comes to ARM v. X86, absolute performance matters as long as the power consumption is within reason. If p/W is all that mattered, we would be running everything on Cortex-A7. You need a certain level of performance and capacity before p/W becomes serious for serious workloads. Thankfully Apple is taking its A-series SOC to that direction.
