AMD A-Series Chips Promises Faster Graphics and Longer Battery Life

Today, AMD is taking the wraps off its Fusion A-Series processors. Whereas the Fusion chips that launched earlier this year were designed to compete with Intel's Atom CPU in netbooks and very-low-cost ultraportable PCs, the A-Series targets midsize mainstream laptops. The CPU cores aren't likely to stand up to Intel's "Sandy Bridge" second-generation Core processors, but the new chips promise superior graphics performance and battery life in laptops priced at between $500 and $1000.

In early January 2011, AMD shipped the first of its Fusion line of processors: the E-Series and the C-Series. Based on the same chip design, those products have been popular and highly acclaimed in premium netbooks and low-end ultraportable laptops, providing CPU and graphics performance that eats Intel's Atom for lunch at competitive costs. AMD calls these processors APUs, or Accelerated Processing Units, to call attention to their ability to offload some parallel processing tasks to the DirectX 11-capable graphics portion of the chip.

Well-received though they have been, the E- and C-Series chips aren't the Fusion processors to get excited about. The real deal is the chip code-named Llano, which has now launched as the A-Series APU. These new chips are meant for midpriced and midsize laptops. Delays in GlobalFoundries' 32-nanometer manufacturing held up the launch of Llano, but now it's finally ready to see the light of day. The chips use a smaller manufacturing process than the 40nm process (produced by TSMC) used by the E- and C-Series, and they include more-powerful hardware and a handful of unique new features.

We don't yet have laptops equipped with A-Series APUs to test, but the new chips look impressive on paper. For impatient statistics fans, here's a rundown of the different laptop model numbers and their specs. (Though it designed the A-Series chips primarily for laptops, AMD will also produce desktop A-Series models that use more power and run slightly faster.

AMD A-Series models; click for full-size image.
AMD A-Series models.

The A-Series CPU Cores

AMD A-Series CPU core block diagram.
The CPU in the A-Series is a modified "Stars" core, the same CPU core found in AMD's Phenom II processor. The chip contains four cores with 4MB of L2 cache, though two of the cores (and half the L2 cache) will be disabled in the A4 models. They're fused off at the fabrication plant, so don't plan on using a software hack to reenable all four cores. This is often done as a way for the manufacturer to salvage chips that would otherwise be considered faulty. Later this year, a new smaller version of the chip with only two CPU cores will hit the market, allowing AMD to market more-cost-effective A4 models and even some new E-Series models. AMD has tweaked the CPU core design, resulting in about a 6 percent improvement in IPC (Instructions Per Clock) over what you'd find in a Phenom II. Still, the clock speeds aren't terribly high, ranging from 1.4GHz to 2.1GHz. Like Intel's Turbo Boost, AMD's Turbo Core technology will automatically step up the clock speed when additional processing power is needed, adding 400MHz to 900MHz for demanding applications as long as the temperature and power draw don't get too high.

From a CPU performance perspective, we don't expect the A-Series to outperform Intel's second-generation Core processors. The advantages for AMD are likely to be in better graphics performance, in enabling GPU accelerated software, and in aggressive power management.

The A-Series GPU

A-Series GPU specs, by model.
The graphics side of the Llano chip is where things get interesting. As it did with the E- and C-Series APUs, AMD is leveraging the design of the latest Radeon 6000 graphics chips. In fact, the portion of the chip devoted to graphics is nearly half--far greater than the comparable part on Intel's chips. The low-end A4 dual-core chips will enable just 240 graphics cores, the quad-core A6 enables 320 cores, and the A8 uses 400 graphics cores. AMD promises graphics performance in the range of 30 to 50 percent higher than Intel's latest Sandy Bridge processors, and in some cases even better.

What the company is really banking on, however, is the ability of the graphics portion of the chip to handle strenuous general computing tasks. This is often called GP-GPU (General Purpose GPU) computing. Programming interfaces like OpenCL and DirectCompute allow developers to tap into the massive parallel number-crunching power of today's graphics chips to run particularly difficult tasks much faster. GP-GPU computing is especially well suited to video editing and encoding, image manipulation, physics, scientific computing, audio manipulation, and similar processor-intensive tasks. So far, few developers are using programmable GPUs for these non-3D-graphics tasks, but the number is growing and AMD is working hard to build the ecosystem.

Of course, the GPU matters in a lot of other ways, too. Modern Web browsers such as Internet Explorer 9, Firefox 4, and Chrome use the GPU to accelerate the way they draw Web pages, especially those that use new HTML5 functions. While the performance and robustness of such GPU acceleration varies from one browser to the next, all three are striving to do more with the GPU. In a modern PC, the GPU is also where the video decoding hardware resides, and the video hardware in AMD's latest GPUs is second to none. In our experience, it decodes more formats with better image quality than other integrated graphics chips do.

The A-Series APUs can also be paired with discrete Radeon graphics chips in what AMD calls Dual Graphics mode. Instead of switching between the integrated graphics chips and the discrete ones, designers can arrange for them to work together for improved performance. There are limits, of course. Only certain Radeon mobile discrete graphics models will work for Dual Graphics mode, and it doesn't exactly double your performance. AMD claims that Dual Graphics mode adds about 30 to 50 percent higher performance over the discrete GPU working alone.

Next: Power Optimizations and Platform Improvements

Power Optimization

AMD A-Series block diagram.
AMD has expended considerable effort improving power efficiency in the A-Series, to the point where the company now claims longer battery life than competing chips from Intel offer. We'll reserve judgment on that point until we test it ourselves, but this is the first time in years AMD has felt comfortable making that claim.

The A-Series chips target the 35- to 45-Watt power requirements of many 13- to 16-inch mainstream laptops. Much of the time, the chips will draw far less power than that, and AMD is proud of its ability to keep power low even in heavy multitasking situations. To accomplish this, AMD has implemented per-core power management that can turn off individual cores and restore them to operation in microseconds, much as Intel has done in its last few chip designs. The chip integrates new digital power-management sensors to measure temperature and current. Together with general reductions in power leakage in the new 32nm manufacturing process and the ability to shut down more of the chip more completely when it isn't needed, everything comes together to provide vastly more-efficient operation than anything AMD has shipped before. In fact, the company claims that A-Series chips will deliver as much as 50 to 60 percent more battery life than its comparable laptop systems of last year. So if an AMD laptop in 2010 gave you 5 hours of runtime, an A-Series system should deliver closer to 8 hours.

Of course, a laptop's battery life is a function of many things: the battery's size and capacity, the display's brightness and efficiency, the hard drive being used, memory speeds, BIOS or UEFI optimizations, and much more. We'll believe that AMD is delivering a lot more battery life than Intel when we see it on a laptop that we test ourselves; but the fact that AMD is claiming over 10 hours of life for some models is extremely encouraging.

The New Motherboard Platform

Accompanying the new processor series is a socket format and--because this chip won't plug into the same socket as Athlons and Phenoms--new motherboard chipsets. There are two chipsets for A-Series mobile products, called Fusion Controller Hubs, and both look pretty good for the price. Both support 6-gigabit-per-second SATA, PCIe Gen2, and various display output formats. The difference is in USB support: The A60M version of the Fusion Controller Hub supports up to 14 USB 2.0 ports and a pair of USB 1.1 ports, while the A70M version swaps out four of those USB 2.0 ports for USB 3.0 ports.

This is good news for fans of USB 3.0. Makers of inexpensive and space-conscious laptops have shied away from USB 3.0 because of the added cost and volume required for the controller chip. But AMD has integrated it into a mainstream motherboard hub ahead of Intel, and it will hopefully result in faster adoption of USB 3.0 in low-cost laptops and desktops.

The mobile A-Series platform can support two SO-DIMM memory modules at speeds up to DDR3-1600, while the desktop platform bumps the limit up to four DIMMs of DDR3-1866. That's a lot of memory bandwidth, but it's necessary to maintain the performance of the integrated graphics.

Pricing and Competitive Pressure

How AMD is positioning its A-Series APUs relative to Intel.
We don't know what the per-unit price of the A-Series processors will be. Laptop buyers will pay for the laptop as a whole, anyway, not for the CPU individually. But AMD's competitive positioning against Intel's processors is noteworthy. The dual-core A4 series is intended for laptops priced in the vicinity of $500, against lower-cost Core i3 chips from Intel. The A6 is where most of the action will be. This steps the users up to a quad-core CPU and more capable graphics for around $600, against laptops using more expensive Core i3 and less expensive Core i5 processors. AMD sees this as the likely highest-volume model. The A8 series is meant to compete with the upper range of Core i5 and Core i7 laptops configured with integrated graphics and priced at approximately $700+.

In either AMD's or Intel's case, adding discrete graphics, more RAM, and other laptop features would drive up the final price. The point is, AMD is aiming at the heart of Intel's market for laptop shipments. We'll let you know how well it performs when we conduct our own hands-on tests of laptops and desktops with A-Series processors inside.

What's Next for AMD

The A-Series is a huge step for AMD. It finally brings to market a CPU based on a 32nm manufacturing process, which Intel began doing more than a year ago. This means smaller, less expensive, less power-hungry chips. More importantly, the A-Series takes the Fusion APU strategy out of the low-power netbook market and delivers a product with the kind of performance that an everyday computer requires. Still, AMD faces some challenges ahead. Though the graphics processor in the A-Series should easily outshine Intel's, the CPU cores will lag behind. AMD hasn't delivered a substantial shift in its processor architecture in about five years.

That will change in a few months, with the processor code-named Zambezi. This CPU, which has no built-in graphics and targets high-performance desktop systems, will be the first to use AMD's new "Bulldozer" CPU design. A radical shift from current AMD CPUs, Bulldozer is organized into modules that incorporate two CPU cores for integer operations, but one powerful shared floating-point math core. A tweaked version of this new CPU core will replace the "Stars" core in A-Series APUs next year. Later this year, AMD will update the Fusion A-Series and E-Series to include a new version of the Llano CPU design that has just two CPU cores, rather than four (the dual-core A4 processor is a quad-core CPU with two cores disabled). Also coming soon is an update to the E-Series and C-Series meant for low-cost netbooks and ultraportables, which will feature a few tweaks and enhancements over the models currently on the market.

If the A-Series APUs have piqued your curiosity, you're not alone: We can't wait to test them for ourselves. Laptops with A-Series APUs should be available within about two weeks, with more models rolling out over the summer. Inexpensive desktop and all-in-one systems with A-Series processors should reach the market in a month or two.

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