The Llano "accelerated processing unit" has been on AMD’s roadmaps for over a year, but surprisingly few details have made it out into the news. To coincide with the International Solid-State Circuits Conference in San Francisco, however, AMD has taken the time to provide fresh technical details and pimp the new design. The folks at EE Times jotted down some of the information.
Llano will include four microprocessor cores, 4MB of L2 cache (1MB per CPU core), and a graphics core on a single die manufactured using GlobalFoundries’ 32-nm silicon-on-insulator process. According to EE Times, the CPU cores will each take up 35 million transistors and 10 mm² of die area. Clock speeds will be upward of 3GHz, and supply voltage should fall in the 0.8-1.3 V range.
AMD will base Llano’s cores on the same "Stars" architecture that powers today’s Phenom IIs. Why not Bulldozer, AMD’s next-generation architecture? When we asked the company that question last year, the company replied that it wanted to use a "well understood, existing core" as the basis for its first 32-nm APU. That decision mirrors Intel’s "tick-tock" execution model, which involves transitioning to new process technologies using existing architectures to minimize implementation snags and delays.
Llano will tread new ground not just with its built-in GPU and 32-nm SOI silicon, but also with new power-management features that will allow each core to fit into 2.5-25W thermal envelopes, "depending on the performance demand." EE Times says those features will include core power gating, which allows each core to be shut off completely from the power supply; improved on-die temperature measurements; and a new clock grid design, which EE Times says "reduced the metal capacitance in the grid by more than 80% and reduced the number of final clock buffers by better than half."
AMD’s latest desktop and mobile roadmaps place the arrival of Llano in 2011 as part of the Lynx and Sabine platforms. On the desktop, Lynx will succeed the existing Pisces and Kodiak platforms that combine Athlon II processors with AMD’s 785G chipset. In the notebook market, meanwhile, Lynx will follow in the footsteps of last year’s Tigris platform.
Correction: Judging by the AMD slides posted at Anandtech, Llano will have thermal envelopes of 2.5-25W per core, not for the whole chip as EE Times states.