I'm not technical wizard by any stretch, but what I understood from that is basically, it's a trade off at any given point in a console's life span. It has significant power, but it comes with maturity and developer experience rather then by default.
In the early years developers use API calls to make a game faster then from scratch while they learn the system their working with, in which case it isn't much faster then the average gaming PC, because it goes through the same abstraction layers.
Later on in the life cycle, performance picks up as developers learn to code direct to metal rather then through the API, increasing speed as you said.
The problem I see here, is that while it may indeed give the performance you said, the counter element is that in that same time frame it took them to master direct to metal on the console to gain that performance, PC performance also gained quite a bit of processing power, and it takes a few years to master the process.
My understanding is the xbox was more graphically powerful then the PC at the time because of the low overhead and less software layers, but after a few years, fell behind because it can't upgrade like a Pc can, and PC's gained rapidly during that time frame, more CPU and GPU power, along with memory bandwidth, surpassing the system. As the console matured to the point of greater graphics output, Pc matured as much, but the console hit a wall years later, that PC did not.
Even though those performance gains maybe true in ideal programming conditions, it isn't always true enough to gain a flat 10x performance across the board. And even when it does become true, you have hardware limitations restricting just how far you can go. It may render 10x faster, but once you hit the ceiling of the GPU's output, it doesn't matter anymore, every chip can only do so much per second. Which is why, consoles may render faster but they can't render enough to exceed 720p except in less demanding titles, and my understanding is they can't use MSAA either.
It does have advantages though. Perhaps someday soon we'll see the end of the API's in windows, linux etc.. and tremendous gains will be made on PC as he stated, I'll be curious to see what my PC is capable of when they comes true.
[citation][nom]kinggremlin[/nom]In this article from 2011, AMD agrees the 10x performance advantage is possible depending on the situation partly because of the handicap layer that DirectX creates. [/citation]