Long article, read at source.
Two months away from the release of the next generation consoles, many have already made up their minds about which machine offers more gaming power before a single game has been released. Compare basic graphics and memory bandwidth specs side-by-side and it looks like a wash - PlayStation 4 comprehensively bests Xbox One to such a degree that sensible discussion of the respective merits of both consoles seems impossible. They're using the same core AMD technologies, only Sony has faster memory and a much larger graphics chip. But is it really that simple?
In the wake of stories from unnamed sources suggesting that PS4 has a significant advantage over its Xbox counterpart, Microsoft wanted to set the record straight. Last Tuesday, Digital Foundry dialled into a conference call to talk with two key technical personnel behind the Xbox One project - passionate engineers who wanted the opportunity to put their story across in a deep-dive technical discussion where all the controversies could be addressed. Within moments of the conversation starting, it quickly became clear that balance would the theme.
Baker is keen to tackle the misconception that the team has created a design that cannot access its ESRAM and DDR3 memory pools simultaneously. Critics say that they're adding the available bandwidths together to inflate their figures and that this simply isn't possible in a real-life scenario.
"You can think of the ESRAM and the DDR3 as making up eight total memory controllers, so there are four external memory controllers (which are 64-bit) which go to the DDR3 and then there are four internal memory controllers that are 256-bit that go to the ESRAM. These are all connected via a crossbar and so in fact it will be true that you can go directly, simultaneously to DRAM and ESRAM," he explains.
"On the SoC, there are many parallel engines - some of those are more like CPU cores or DSP cores. How we count to fifteen: [we have] eight inside the audio block, four move engines, one video encode, one video decode and one video compositor/resizer," says Nick Baker.
"The audio block is completely unique. That was designed by us in-house. It's based on four tensilica DSP cores and several programmable processing engines. We break it up as one core running control, two cores running a lot of vector code for speech and one for general purpose DSP. We couple that with sample rate conversion, filtering, mixing, equalisation, dynamic range compensation then also the XMA audio block. The goal was to run 512 simultaneous voices for game audio as well as being able to do speech pre-processing for Kinect."
"Every one of the Xbox One dev kits actually has 14 CUs on the silicon. Two of those CUs are reserved for redundancy in manufacturing, but we could go and do the experiment - if we were actually at 14 CUs what kind of performance benefit would we get versus 12? And if we raised the GPU clock what sort of performance advantage would we get? And we actually saw on the launch titles - we looked at a lot of titles in a lot of depth - we found that going to 14 CUs wasn't as effective as the 6.6 per cent clock upgrade that we did."
p.s. Let's drink every time they say "balance".