ARM unveils next-generation mobile graphics chips

The chip maker has given details of three new Mali GPUs, to appear in smartphones and tablets in 2013

David Bayon
6 Aug 2012

ARM has unveiled three new mobile graphics chips designed for use in next-generation smartphones, tablets and smart TVs.

The Mali T624, T628 and T678 build on ARM’s Midgard graphics architecture, and join three existing chips in the T600 range. Scalable and designed for GPU computing, the new additions will increase performance over their predecessors by up to 50%, essential as resolutions climb and interfaces become more demanding.

“In the mobile space, user interfaces are becoming more fluid,” Steve Steele, Head of Product Management at ARM’s Media Processing Division, told PC Pro. “Refresh rates are faster, screen resolutions are bigger, and on each of those pixels we have to do more because of content that’s becoming more complex.”

ARM’s response has been to develop two product lines in parallel: the graphics-only T200 and T400 ranges, found in some of today’s top mobile devices, and a separate T600 range that focuses on both graphics and GPU compute processes to meet the needs of the next generation.

The three new parts support OpenCL Full Profile, Google RenderScript, and 64-bit double precision to build the CPU and GPU together into “an ARM compute platform”. But they’ll also offer significant performance improvements.

“They’re going to get an up to 50% increase... and that comes in two different parts,” said Steele. “One is that we’ve been able to increase the maximum frequency that’s available in the design. Second to that, we’ve also been able to increase the architectural efficiency of the design. You can run faster, but for each of those faster megahertz you’re going to do more work as well.”

Mali T600 architecture

The T624 has four cores, with the eight cores of the T628 and T678 offering a twofold and fourfold increase in graphics performance respectively. This is because the T678 - aimed at tablets - has a different pipeline structure within each shader core. The Mali T624 and Mali T628 have two arithmetic pipelines, a single texturing pipeline and a load/store pipeline. “For the Mali T678… we’ve doubled the number of arithmetic pipelines," said Steele. "That directly translates to double the gigaflops performance.”

Mali T600 Shader Core architecture

Licensees will be able to implement anywhere between one and eight cores on the T678, between four and eight cores on the T628 and between one and four cores on the T624. “It’s entirely their choice,” said Steele. “The IP is very configurable. It’s basically a solution for pretty much any purpose that’s out there.”

Steele expects the first devices using the new Mali chips to arrive this time next year.

The 2012 generation

The three existing members of the Mali T600 range, first announced back in 2010, will begin making their consumer debut in devices from September this year. ARM claimed its top-end T658 has ten times the graphical power of the Mali 400 MP in the Samsung Galaxy S II, while the lesser T604 was thought a remote possibility for the Galaxy S III before ARM introduced the updated Mali 450 MP.

When the T604 was announced, ARM VP Lance Howarth made bold claims about the chip’s gaming potential, saying “we’re really now in the realm of an Xbox 360 in a mobile phone”.

ARM expects its 25 hardware partners to ship “well over 100 million” Mali-powered units in 2012.

Leading on GPU computing

The T600 range also supports ARM’s own Adaptive Scalable Texture Compression (ASTC) standard, which ARM hopes will become widely used across the industry.

“We’ve decided not to keep it to ourselves," explained Steele, "so we’ve donated it to Khronos – the industry standard body for graphics. Khronos are going to have that as a texture compression extension for all of their OpenGL and OpenGL ES APIs. Different companies put forward different proposals, and ours was chosen over the others because it was clearly technically superior in terms of getting a certain level of image quality for a certain level of data compression.”

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