Mobile chip performance is
accelerating at such an incredible rate that it may soon invade our desktops,
as we discover
AMD versus Intel. Athlon versus Pentium.
Radeon versus GeForce. For years we’ve tracked the ongoing battles between the
giants of processing and graphics. Now, however, something strange is
happening, something that could leave the latest developments in desktop CPUs
and GPUs looking like a sideshow. What if the real battle for the future of
computing isn’t between Intel and AMD, but Intel and ARM?
What if the next crucial step in graphics
technology comes not from Nvidia, but from Imagination Technologies or
Qualcomm? What if mobile processor technology is the mainstream?
Mobile
chip performance is accelerating at such an incredible rate that it may soon
invade our desktops
Ever since the rise of the smartphone and
then the tablet, the mobile and desktop computing paths have been converging.
The PC isn’t dead Gartner still put global sales at 87.5 million units in the
second quarter of 2012 but smartphone sales were 154 million in the same
quarter, and tablet sales are set to grow to 369 million a year by the end of
2016.
What’s more, we’re seeing an explosion of
mobile processing power, with the potential to transform computing. We’re not
merely talking mobile CPUs and GPUs that reach desktop levels of power, but
mobile architectures that might invade the desktop.
The state of play
Just as the desktop processor market
belongs to Intel, so the mobile processor market is dominated by ARM. The
British firm designs and licenses its microprocessor architectures to others
rather than manufacturing chips itself, and the list of partners making
system-on-a-chip (SoC) products includes Samsung, Apple, Nvidia, Texas
Instruments and Broadcom. Qualcomm licenses the ARMv7 instruction set but uses
its own architecture in its Snapdragon SoC line, while Intel has its own
Medfield SoC for smartphones and Clover Trail SoC for tablets, both based on
the Atom architecture.
However, the CPU is only one part of the
SoC picture: since it’s effectively a computer, it also needs to incorporate a
memory subsystem, an I/O subsystem and a GPU. Not surprisingly, that last item
has become the focus of intense competition, with ARM licensing its Mali GPU
cores, Qualcomm designing its own Adreno GPUs, and Nvidia showcasing its
expertise with its Tegra SoCs. Meanwhile, the UK’s Imagination Technologies has
reversed the fortunes of its PowerVR technology, taking it from desktop failure
to the GPU that powers the iPhone and iPad.
A few years ago, the idea of comparing SoCs
with desktop processors would have seemed laughable, but not anymore. Of
course, direct comparisons are difficult. As Laurence Bryant, director of
mobile solutions for ARM, puts it, “it’s always hard to draw a direct parallel,
because ARM processors are working in the sub-watt category, whereas your
desktop processor may be 40W or more in terms of power consumption.”
Nvidia’s technical marketing director Nick
Stam also sounds a note of realism. “They’re not as powerful as today’s Sandy
Bridge or Ivy Bridge, and that difference is going to be maintained well into
the future because of, basically, power.” However, the gap is closing. “I would
say today that the Tegra 3 SoC performs close to a mainstream CPU that’s, say,
maybe three years old. I know there are certain tests where we’re similar to a
low-end Core 2 Duo.”
In terms of simple instructions per second,
ARM’s next quad-core Cortex-A15 processor isn’t far behind a six year old Core
2 Extreme QX6700, at 35,000 Dhrystone MIPs (millions of instructions per
second) against 49,161 Dhrystone MIPS. That’s a lot of performance in a
low-power SoC. Meanwhile, Intel’s Clover Trail SoC looks set to banish the bad
memories of the old netbook Atoms, with reports of more than acceptable
performance in Windows 8.
The
ARM Cortex-A15 processor.
It’s a similar story when it comes to
graphics. Nvidia’s Stam says Tegra 3 is “not as powerful as the chip in a
PlayStation 3 today, but give us another generation or two and I would say
that, both from the CPU and GPU side, the SoC would be comparable to a
circa-2006 PlayStation 3 in pure processing FLOPS [floating point operations
per second].”
This isn’t inconceivable. Imagination
Technologies claims its next-generation SGX Series6. GPUs will push more pixels
per second than a mainstream GeForce 7600 GT graphics card of that same era,
with a 5-gigapixel fill rate as opposed to 4.48. What’s more, Imagination
claims that its tile based deferred rendering technology makes that 5-gigapixel
fill rate look like 13 gigapixels on the screen, which would put the SGX
Series6 GPU ahead of a GeForce 9600 GT GPU of two years later.
As David Harold of Imagination Technologies
puts it, “mobile is behind in terms of raw fps [frames per second], but not so
much in terms of features.” With support for DirectX 11, OpenGL and OpenGL ES 3
features, today’s mobile processors can produce mobile content that “to most
eyes, looks just as good as anything on PC or console,” says Harold. “You and I
might appreciate that there are techniques being used to create that effect
less complexity in some areas, a little less aliasing on the smaller screen but
the proof is in the experience.”
