Harkening back to when he joined ARM, Segars said: “2G, back in the early 90s, was a hard problem. It was solved with a general-purpose processor, DSP, and a bit of control logic, but essentially it was a programmable thing. It was hard then – but by todays standards that was a complete walk in the park.”
He wasn’t merely indulging in “Hey you kids, get off my lawn!” old-guy nostalgia. He had a point to make about increasing silicon complexity – and he had figures to back it up: “A 4G modem,” he said, “which is going to deliver about 100X the bandwidth … is going to be about 500 times more complex than a 2G solution.”
A very interesting look a the state of the art in microprocessor manufacturing, The Register talks with one of the principles at ARM, the folks who license their processor designs to almost every cell phone manufacturer worldwide. Looking at the trends in manufacturing, Simon Segars is predicting a more difficult level of sustained performance gains in the near future. Most advancement he feels will be had by integrating more kinds of processing and coordinating the I/O between those processors on the same processor die. Which is kind of what Intel is attempting to do integrating graphics cores, memory controllers and CPU all on one slice of silicon. But the software integration is the trickiest part, and Intel still sees fit to just add more general purpose CPU cores to continue making new sales. Processor clocks stay pretty rigidly near the 3GHz boundary and have not shifted significantly since the end of the Pentium IV era.
Note too, the difficulty of scaling up as well as designing the next gen chips. Referring back to my article from Dec.21, 2010; 450mm wafers (commentary on Electronista article), Intel is the only company rich enough to scale up to the next size of wafer. Every step in the manufacturing process has become so specialized that the motivation to create new devices for manufacture and test just isn’t there because the total number of manufacturers who can scale up to the next largest size of silicon wafer is probably 4 companies worldwide. That’s a measure of how exorbitantly expensive large scale chip manufacturing has become. It seems more and more a plateau is being reached in terms of clock speeds and the size of wafers finished in manufacturing. With these limits, Simon Segars thesis becomes even stronger.