When Intel launched the first two processors based on the new Skylake
architecture at Gamescom a few weeks ago, it didn't share much
information about what's new and why they are faster or better than
their predecessors. The enthusiast-oriented Core i7-6700K and Core
i5-6600K are only the tip of the iceberg though; Intel will launch many
more models across price tiers and device segments over the next year.
While
details such as speeds and specifications of individual SKUs have not
been made public, Intel did share a whole lot of information about the
architecture as a whole at the annual Intel Developer Forum this week.
Over the course of several technical briefings, we were able to build a
high-level overview of what Skylake (formally known as the
sixth-generation Core architecture) does differently and what users can
expect.
This overview paints a picture of a hypothetical Skylake
processor with a superset of all possible features. Diagrams shown do
not represent any actual product. It is likely that there will be models
that do implement a majority of these features, if not all, but we do
not know at this point how Intel will differentiate products at
different tiers in its hierarchy.
First of all, Skylake has been
designed with a much wider range of target devices in mind than any
previous generation. There is a 20x scale in terms of TDP, which
represents power consumption and heat output. At one end of the scale,
there will be 4.5W parts for ultralight tablets - these will succeed the
current products in the Core M lineup. At the other extreme will be 91W
parts, such as the two already launched.
With tablets and other
portable form factors in mind, another big change this generation is the
incorporation of IO (Input and Output) functionality that has not been
integrated into processors before. Key amongst these is a camera ISP
(Image Signal Processor) that can handle up to four 13-megapixel cameras
(but only two simultaneously). That might seem excessive, but stereo
imaging is key to Intel's RealSense efforts.
4K video recording at
30fps or 1080p at 60fps will be supported. Camera capabilities will
include face detection and recognition, still capture during video
recording, concurrently recording two video streams, zero-lag burst
captures, and HDR. ISP integration reduces the cost and complexity of
designing devices, while getting smaller and smaller.
Power
reduction has been at the forefront of CPU development for years, and
Skylake takes things a step further by dedicating separate
fixed-function logic for tasks such as 4K video decoding, streaming, and
transcoding. New formats that can be accelerated include HEVC, AVC,
SCc, VP8, and MJPEG. This allows the bulk of the CPU to stay idle while
performing an otherwise stressful task, reducing power draw. Beyond
that, power gating is even more granular than before. Very specific
parts of the CPU can be turned off when not required.
Intel
reminded us that all power savings are the result of better efficiency
in the architecture, since Skylake is not based on a new, smaller
manufacturing process. By pushing more instructions through per clock
cycle and further reducing occasions when the CPU is waiting for data
from a cache or main memory, the CPU can do its work and switch to a
lower power state sooner.
In another first, Skylake processors
will take over the duty of deciding when to switch between power states,
which has until now been handled by the operating system. Intel calls
the new technique SpeedShift, which it says will allow it to switch
states more rapidly, providing processing power on demand but also
shutting things down with more agility.
Not all improvements cater
to the low-power end of the spectrum. Intel has taken into
consideration the needs of enthusiasts and overclockers. The highest-end
K-series CPUs (and possibly some others) allow for very fine-grained
voltage and frequency adjustments. The base clock has been liberated
from being tied to the strictly controlled PCI Express bus clock, and
can be pushed in 1MHz increments. There are independent multipliers for
the processor, memory and graphics units. DDR4 memory can be pushed to
up to 4133MHz.
There's also good news on the graphics front - the
9th-generation integrated graphics logic will support DirectX 12,
Vulkan, OpenCL 2.x and OpenGL 5.x. Laptops will be able to drive 60Hz 4K
displays using just the integrated graphics. Devices will be able to
drive displays of up to 4,096x2,304 at 60Hz over DisplayPort, or lower
resolutions over HDMI.
Intel will use dedicated embedded DRAM
across more of its lineup instead of reserving it for top-tier CPUs with
Iris Pro graphics. There's also a difference in the way it is
implemented; rather than being effectively a fourth-level cache, it will
act as a fully coherent memory space that can be allocated for any
purpose. Intel says that its graphics driver will decide what data is
available in the eDRAM, which might including data not traditionally
considered worth keeping within the processor's caches.
There are
new functions which aim to improve platform security. SGX, or Software
Guard eXtensions which allow for the creation of "enclaves" in which
data cannot be accessed by any running process other than the one that
created it. According to Intel, not even processor debugging tools will
be able to retrieve code or data within an SGX enclave. This will
protect against attacks that manage to get elevated OS-level
permissions.
Undoubtedly, more information will become known after
the formal Skylake launch. There's still much more that isn't widely
known We hope to have much more insight into Intel's technology and
strategy soon.
Disclosure: Intel sponsored the correspondent's flights and hotel for the event in San Francisco.
Intel's Strategy for the Post-PC World Begins to Take Real Shape22 August 2016
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