Of course, as a tablet chip, Bay Trail makes extensive use of the latest power-management techniques. Both the CPU and graphics cores can scale their clock frequencies and operating voltages in response to varying workloads. In addition, the chip can share its power budget between its major components, allowing additional performance headroom in certain cases.
For example, the image above cycles through several potential scenarios where individual CPU cores or other portions of the chip aren't in use. These units are powered down, freeing up thermal headroom. In response, the still-busy CPU cores or integrated graphics can temporarily exceed their usual clock speeds.
Oddly, Intel calls this "Burst Technology," rather than Turbo Boost, in the context of the Atom. The branding is kept separate because the Turbo tech in the Core processor lineup is still more advanced, with a broader dynamic operating range.
Many of the big components of the SoC are in their own power islands, with separate voltage supply rails, power gates to shut off inactive areas, or both. The illustration above offers a quick glimpse of Bay Trail's dynamic power management in action via thermal imaging. In one case, only two cores appear to be active. In the next, all four CPU cores are active. In another, they all look to be powered down.
The final shot shows an almost completely dark chip.That's presumably one of Bay Trail's idle states. Like Haswell, this SoC pursues power savings, even between keystrokes, by dropping into a series of "active idle" states known as S0ix. These power states are managed in hardware and should be transparent to software and the OS. The deeper the sleep, the longer it takes for the chip to wake up. Intel's Rajesh Patel again wouldn't offer too many details about S0ix behavior in Bay Trail, but we'd expect much more aggressive pursuit of deeper idle states than in Avoton.
The Atom Z3000 series
Intel is spinning Bay Trail into five different models that make up the Atom Z3000 series, as shown below. These chips have been sampling for months now, as I understand it, and Intel anticipates that products based on them will be available for the holiday season.
The Atom Z3000 series will occupy tablets and convertible systems with screen sizes ranging from 7" to 11" and prices up to about $599. There may be some overlap, but generally speaking, systems costing more than that will likely be based on Haswell rather than Bay Trail. Intel estimates that it has 30 different design wins for the Atom 3000 series at present, and it expects that list to grow.
The Z3000 series will support both the Windows 8.1 and Android operating systems at launch, but the Windows 8.1 situation is a bit tricky. Initially, only the 32-bit version of Win8.1 will be fully supported with connected standby capability, a crucial feature for tablets. Intel has pledged to deliver full 64-bit support with connected standby in the first quarter of next year. Apparently, the hold-up is software; the company claims the hardware is ready.
Obviously, the initial lack of 64-bit support isn't a deal-breaker in tablets, since the scads of Android and iOS-based tablets in the market are 32-bit devices. Still, being stuck with 3.5GB of usable memory in Windows isn't ideal, especially for convertible devices that dock with a keyboard and should be more than capable of serious productivity work. The delay in 64-bit support at least mitigates one of the advantages of going with a Wintel device over something else.
I'd like to show you the power specifications of these new Atoms, but Intel has decided not to be too specific on that front. Because of all of the dynamic power management at work, there's some dispute over the proper power metric for this class of chip. (Intel has two specs, TDP and SDP, that it uses in different contexts.) We will talk a little bit about measured power use shortly, though.
In addition to the Atom Z3000 lineup, Intel will offer Bay Trail chips for traditional notebooks and desktops under the Pentium and Celeron brands. In fact, Intel's NUC group has Bay Trail-based systems on its roadmap.