Not exactly a surprise, because we've all been expecting Cortex A15 to be more powerful than Cortex A9-based chips, even if they come in quad core versions, but it seems Sony agrees that dual core phones can be more powerful than single core ones, and they can also offer higher energy efficiency under maximum load.
Tegra 3 can be a very efficient chip because it has that 5th core that handles most of the lower-priority tasks, which helps save battery, and also because its 4 cores are not always in use, even when the application requires maximum performance. That's because most apps are still not optimized for quad cores. Under maximum load, with 4 cores, Tegra 3 does use quite a bit more power than say a dual core S4 chip. But as I said, under most circumstances the Tegra 3 should be very efficient as well.
However, I believe having a quad core processor in a phone right now is a little premature, especially when a lot more can be done with dual core chips, even if that means simply raising the frequency, like TI is doing with the OMAP 4470 (1.8 Ghz). But that should generally give increased performance for lower power consumption, than adding more cores.
"We're going to join quad-core when we feel that the performance matches the battery efficiency," he said. "Because right now we don't feel that is there. What we are going to be doing in the second half of the year is moving to the Cortex A15 architecture, which we feel outperforms the current quad-core architecture.
"You'll see in 2013, as we're evaluating the quad-core performance where it makes sense, where you're not suffering in quality and the performance truly is there, and there really is something that demanding applications need," he contiuned." That's when we make the right move to quad-core."
Again, Sony is mostly right here, but there's also the feeling that Sony is just being defensive, because they are still not part of the manufacturers who can put out the best technology on the market on time. They've usually come out with it 6-12 months later, when it was already time to switch to even newer technology. So I'm hoping Sony will be one of the very first to use the Krait chip, perhaps in Xperia Play 2 even, because if they don't then, it just means they are still not competitive enough with the other manufacturers.