The Brazos platform is intended by AMD as a basis for compact and energy-efficient systems. It consists of a Bobcat-microarchitecture processor with integrated graphics core and a highly integrated mainboard with appropriate chipset.
At the current moment, AMD offers two types of processors as a part of Brazos platform. They are codenamed Ontario and Zacate. The former has a heat dissipation of 9 watts and is targeted at the netbook market. The latter has a TDP of 18 watts and is meant for nettops and entry-level desktops as well as for inexpensive notebooks.
Both types of processors feature two Bobcat cores and a DirectX 11-compatible graphics core of the Mobility Radeon HD 6000 class. The advanced graphics is one of the key distinguishing features of AMD’s energy-efficient processors in comparison with Intel’s Atoms. The Ontario and Zacate also have a PCIe 2.0 x4 controller and an integrated memory controller that supports single-channel DDR3-1067 SDRAM. All of the mentioned components reside in a single semiconductor die manufactured on 40nm tech process at TSMC facilities.
Bobcat cores are compact and the Ontario and Zacate were designed with energy efficiency and low manufacturing cost in mind, therefore the semiconductor die is very small, measuring a mere 75 square millimeters. To give you some reference point, this is even smaller than the size of Pineview-core Atom processors.
Notwithstanding the compact dimensions, the Ontario and Zacate silicon contains a full-featured Cedar graphics core with two SIMD units each comprising 40 stream processors. The graphics core also has eight render output units. In the multimedia department, it features a third-generation Unified Video Decoder that offers hardware acceleration for video playback in MPEG-2, VC-1 and H.264 formats. Thus, the Ontario and Zacate can be said to incorporate a graphics core like the Radeon HD 5450 with DirectX 11 support.
It is the incorporation of an advanced graphics core into these new energy-efficient processors that gives AMD the reason to call them not just central processing units (CPUs) but accelerated processing units or APUs. The new term has been coined to additionally emphasize the compatibility of the integrated graphics core with the OpenCL and DirectCompute APIs as well as the availability of the hardware HD video decoder UVD3. This means that the graphics core can offload the CPU in certain applications, improving the overall system performance.
At the current moment, the model range of the Ontario and Zacate APUs includes four products:
The Ontario and Zacate specifications make it clear why AMD makes such a point of calling them APUs rather than conventional CPUs. The graphics core incorporated into them is far!20more advanced than the general computing core. While the CPU part with the Bobcat microarchitecture is comparable to the Intel Atom, i.e. represents a rather weak CPU by today’s standards, the Cedar graphics core with 80 stream processors is perhaps one of the highest-performance integrated graphics available today. Of course, when coupled with a low-speed CPU, it is going to be redundant for classic 3D applications, such as games, because it will be limited by the CPU performance. The benefits of the high-performance graphics core witl advanced computing resources are going to become apparent in traditional computing tasks.
Of course, this calls for further improvements of the GPGPU concept and for making GPGPU-compatible applications widespread. In fact, this work has been underway for a while already but now we can really hope that there will be more such applications available. There are currently only a few programs that are optimized for AM@’s new APUs but they already include not only conventional video players or video transcoding tools. There are next-generation browsers (particularly, Internet Explorer 9) and, for example, some office applications (PowerPoint 2010) that can make full use of the capabilities of Ontario- and Zacate-based systems. Thus, AMD’s APU concept has a chance to make low-performance CPUs with the Bobcat microarchitecture appealing to the end-users with something else than just low pricing.
Besides an APU, the Brazos platform includes a companion chip that adds`support for peripheral interfaces. The chip is called Hudson FCH (Fusion Controller Hub) and supports six SATA 6 Gbps (without RAID option), 14 USB 2.0 ports, four PCIe 2.0 lanes, and HD Audio among other things.
And again AMD made sure the chip wouldn’t be a big energy consumer. Being rather simple, the Hudson is manufactured on 65nm tech process and has a TDP of 4.7 watts, which means that the peak power consumption of the whole Brazos platform in its maximum configuration targeted at nettops and fast netbooks is only 23 watts. This is 30% lower than that of the second-generation ION, by the way, making the Brazos look like a next-generation “ION”: the multimedia capabilities of the Ontario and Zacate APUs are no worse than those of the Nvidia ION, the computing performance is comparable to that of the Intel Atom, and the power consumption and heat dissipation are very low as well.