AMD's 2012 Mobile Strategy Revealed: Trinity Becomes Fusion

AMD recently introduced the processor codenamed Trinity. At first, Trinity will power a series of "ultrathins" and other mobile designs, while the desktop version will follow soon afterwards. In this article, we go deep into what Trinity brings to the market.

The Trinity die is manufactured at the 32nm using SOI technology at GLOBALFOUNDRIES in Dresden, Germany. It packs 1.3 billion transistors, which is slightly down from Llano's 1.45 billion. Yet the die measures 246 mm², while Llano comes in at 228 mm². Why is that? One possible explanation could lie in the Piledriver design that is an evolution of Bulldozer. Bulldozer sparked some controversy to be inefficient in terms of transistor density. Compared to Llano, Trinity is a bit worse, but still quite good thanks to the very dense GPU design – more on that later.



Still this is an interesting point to make since the original design goal of Bulldozer and its successors was to improve transistor efficiency by sharing certain components of the CPU cores. It appears this strategy has backfired so far. AMD never officially explained why that is the case. Rumor has it that this is a side-effect of automatic silicon design tools compared to designs "handcrafted" by engineers. Given Bulldozers lackluster performance it remains to be seen how long AMD will stay on that train. AMD has since promised to improve performance significantly with each passing generation. The revised Piledriver cores will soon show how these promises translate into real world clock for clock performance.



AMD touts a 29% increase in productivity and a 56% increase in visual performance. These claims are based on the figures of the A10-4600M (Trinity) vs. an A8-3500M (Llano) in PC Mark Vantage (productivity) and 3D Mark Vantage (visual). The productivity increase looks a bit moot, considering the difference in clock speed. The 3500M is a 1.5GHz (2.4GHz Turbo) quad-core Husky CPU (K10.5 architecture with minor enhancements), while the 4600M is a 2.3GHz (3.2GHz Turbo) quad-core Piledriver CPU (2 modules containing 2 integer 1 FP core). So the application performance boost comes mainly from clock speed.

This is not a good sign for Piledriver performance going forward. Bulldozer already was unable to match its predecessor clock for clock, much less Intel’s offerings. It seems this will repeat similarly with Piledriver. Now we don't want to put Piledriver in a bad light, but we don't like this trend. Piledriver brings some improvements over Bulldozer, namely some instruction set enhancements, like FMA3 support and 16-bit floating point support (F16C).


AMD Piledriver CPU core improved on many fronts compared to its predecessor, the Bulldozer core.

Additionally AMD claims it brings IPC improvements, without quantifying it in detail. The L1 TLB now holds 64 entries, up from 32 which should help with performance. As the slide from AMD shows, a lot of other small things have been improved. So it might be more efficient per clock compared to Bulldozer, but the first official benchmark numbers indicate that this improvement will be only minor. Still before final judgment independent benchmarks covering a wide range of workloads should be evaluated.

Despite our skepticism regarding the CPU performance, it is still remarkable that AMD is able to fit these cores into ever smaller thermal envelopes. The company cited leakage reduction as a Piledriver improvement as well. The notebook models of Trinity will come in 17W, 25W and 35W variants. That’s down from 35W and 45W with Llano. In their first briefing, AMD gave a frequency range of 2.0GHz to 3.8GHz for the CPU and 424MHz to 800MHz for the GPU. But beware, this also includes desktop models, which are planned to be launched in 65W and 100W bins during Computex Taipei 2012, which is being held from June 5-9 in Taiwan.