Speaking at the Hot Chips engineering conference at Stanford University, Microsoft chip architect John Sell said the Xbox One’s main processor is a gargantuan beast, co-designed with Advanced Micro Devices and manufactured by contract chip manufacturer Taiwan Semiconductor Manufacturing Co.
The chip covers an area of 363 square millimeters and is built in a 28-nanometer state-of-the-art manufacturing process. It has 5 billion basic components, known as transistors, on a single chip that combines a microprocessor, graphics processor, and 47 megabytes of memory.
As one member of the audience remarked, that mean it’s a big chip. Such chips are hard to manufacture, as any small defect can render a chip inoperable. And the larger a chip, the more prone it is to small defects.
To deal with that, Sell said Microsoft designed in redundancies into the chip where it could, so that if one section was inoperable, it doesn’t kill the whole chip. Nevertheless, it means that it won’t be easy to churn out millions of such chips.
To make the chip more power efficient, Microsoft designed small islands and gates within the chip that could switch off certain areas so the overall chip consumes less power. Such techniques are standard in big chip projects these days, and they mean that only the parts of a chip that are being used are drawing power.
The central processing unit (CPU) has eight 64-bit Jaguar cores designed by AMD.
The graphics section of the main processor has 15 special processors that can handle things like graphics or physics processing. Data highways can transfer bits at a rate of 200 gigabytes per second or more across different parts of the chip. The audio subsystem has two dedicated vector cores.
Microsoft disclosed some details, but left many important pieces out. Evidently, Microsoft doesn’t want to tell all of its competitors about how well designed its system is.