The Fusion program by Advanced Micro Devices is probably among the most significant hardware innovations in the recent years since the introduction of multi-core x86-64 microprocessors with integrated memory controller. Putting a graphics processor inside the central processing unit is not just fusing two different computer components, but ultimately such hybrid chips called accelerated processing units (APUs) will open up new computing paradigm and new types of processors.
For AMD, the Fusion initiative is not only a vehicle to ride into heterogeneous multi-core future, but also the prove that the company did the right thing when it acquired ATI Technologies back in 2006 and essentially sold-off its manufacturing facilities in 2008.
But what we actually know about the Fusion program by AMD, except the fact that it has cost billions of dollars? What AMD hopes on? Why did it take so long to release the first Fusion chip? What are AMD's expectations for the forthcoming Brazos platform for low-cost notebooks and netbooks powered by Ontario and Zacate APUs? What kind of benefits should consumers expect from the new hybrid processors and what should not be expected? Today we are talking to Godfrey Cheng from AMD to find out more about the past and present of Fusion from the first hands.
X-bit labs: Hello, can you introduce yourself to our readers, please?
Godfrey Cheng: My name is Godfrey Cheng and I am director of client technology unit at AMD. My focus is primarily around technology planning for our products and developing plans to use our Fusion APUs to accelerate current types of computing as well as new ones enabled by Fusion APUs.
In general words, Mr. Cheng is one of the key people responsible for success of AMD Fusion business. While the first Fusion products are developed for low-cost notebooks and multimedia netbooks, eventually the APUs will be inside desktops and notebooks and will represent the largest chunk of AMD's business in terms of revenue. The success of all these platforms will be determined not only by performance supplied by chips, but also by software that should be able to take advantage of parallel compute capabilities of the forthcoming APUs.
Fusion Hardware: When 1+1≠2
What Took So Long?
AMD originally promised to release hybrid chips with integrated x86 processing elements and graphics processing elements in late 2008 or early 2009. But after numerous failures and a couple of faulty prototypes the company made major to its roadmaps and delayed the actual Fusion products to 2010 - 2011 timeframe and at the same time boosted specs of the APUs with DirectX 11 graphics cores as well as new CPU micro-architectures.
X-bit labs: The road to Fusion of technologies from AMD and ATI has been very long and rather hard. What were - and still are - the main challenges for integration of CPU and GPU?
Godfrey Cheng: If you look at the very high level, people automatically confuse that this is a simple integration of a CPU and a GPU [into a single piece of silicon]. This is not the case. What we are doing is we are adding parallel computing unit and additional fixed-function units into the mix for the APU. [...] We are also adding new program paradigm with OpenCL and DirectCompute.
There are natural hardware challenges. We do have to innovate two physically different devices, glue them alltogether and make sure they work with new protocols like OpenCL.
X-bit labs: So, it was not the hardware issue, but it was a complex of problems that you had to solve first before proceeding with an actual product?
Godfrey Cheng: Yes. You can look at it this way. we would view Fusion as not only products but we need to plan our architecture for the current generation and two-three generations down the road. This does take time and it will see our products take big steps along the way in innovation. We need to make sure they are forward and backward compatible and that takes some time.
X-bit labs: Basically for Ontario and Zacate you needed not only Bobcat micro-architecture, but also OpenCL and DirectCompute-compliant graphics cores and other things in place before fusing them in one chip?
Godfrey Cheng: CPU architecture, OpenCL/DirectCompute-compliant GPUs as well as fixed-function hardware. In the Fusion parts that we are going to launch early next year we have updated the UVD block, for example.
In mid-2010 the company decided to switch release timeframes of lower-power Ontario/Zacate and high-performance Llano APUs. Apparently, the yields of Llano, which is to be made by Globalfoundries using 32nm silicon-on-insulator process technology, were lower than expected; meanwhile, yields of lower-performance Ontario/Zacate produced at 40nm node of Taiwan Semiconductor Manufacturing Company (TSMC) were fine. As a result, the era of Fusion starts with low-cost low-power chips.
X-bit labs: What was the reason why you decided to use TSMC process technology and not Globalfoundries' fabrication processes?
Godfrey Cheng: At the very high level, AMD is now a separate company from Globalfoundries. Both Globalfoundries and TSMC are important partners for us. As a company, we are interested in having more than one source for our products. At a technical level, we actually have a lot of IP [libraries] with TSMC in terms of our GPUs, display and analogue technology. So, it is easier task to integrate under TSMC because of those display and analogue libraries.
X-bit labs: What version of TSMC's 40nm process technology did you use? As far as I understand, you used TSMC's 40LP flavour for Ontario and Zacate, am I correct?
Godfrey Cheng: What we did was that we leveraged as many of the technologies as we could from the GPU side.