September 13, 2012, 1:48 PM — For PC users on the go, machines with a long battery life are essential, but so is performance. Balancing these contradictory requirements lies at the heart of Intel's new CPU architecture, code-named Haswell, which is expected to appear in shipping tablets, Ultrabooks, and other computers in 2013.
At the 2012 Intel Developer Forum earlier this week, Intel dove deeper into what makes Haswell tick.
Or maybe "tock" would be a more appropriate verb, since Haswell represents the "tock" in Intel's CPU development program. Intel uses "tick/tock" to denote its CPU development strategy. A "tick" occurs when Intel tweaks an existing CPU design relatively little but takes advantage of all the efficiencies of a new manufacturing process. Ivy Bridge, for example, was a tick, improving on Sandy Bridge only incrementally, but moving to 22nm. Intel always builds new architectures, like Haswell, on proven manufacturing processes--and Intel's 22nm manufacturing process has been well shaken out, thanks to the company's Ivy Bridge line. So Haswell constitutes a "tock."
Haswell isn't just another Intel PC processor, though. Intel is talking about producing Haswell-based processors across a range from dual-core chips that run at less than 10 watts (making them suitable for tablets) to quad-core desktop CPUs that can outperform the fastest Ivy Bridge processors.
How did Intel hit its aggressive target of a 20-fold improvement in power efficiency? In answering this question, we need to looking at Haswell's power management technology before diving into the CPU proper.
Modern CPU power-management technology cuts power to large chunks of the processor when doing so makes sense. A special processing unit--which the company calls it the Power Control Unit--built directly inside the main CPU manages power almost to the transistor level. The PCU looks at which parts of the processor are idle, and turns individual parts on and off as needed.