Which CPU? Intel Sandy Bridge vs. AMD Fusion

Over the next few weeks, Intel and AMD are set to unleash two new families of CPUs: Sandy Bridge (Intel's 2nd Generation Core processors) and Fusion, respectively.

These new processing chips offer a range of exciting improvements over existing CPU architecture, including on-board graphics chipsets, increased power efficiency and Full HD video optimisation. If you're curious about the new chips, read on for an inside look at Intel's Sandy Bridge and AMD's Fusion APU (accelerated processing unit).

Intel's Sandy Bridge

Sandy Bridge is Intel's second generation of Core processors, incorporating new Core i3, Core i5 and Core i7 models. The new processors will only work in motherboards that have an LGA-1155 CPU socket; they feature the processing chip, graphics adapter and some I/O functions together on the same physical piece of silicon. On the first generation Intel Core CPUs, the graphics were in the same physical package as the CPU, but not on the same silicon. In the 2nd generation Core CPUs, the graphics have been properly integrated with the CPU. For the end user, this translates to faster and more efficient computers — especially in the notebook sector (the high-end Core i7 processors will allow laptops to handle eight-way multitasking, for example).

Sandy Bridge: What's inside?

The new Intel socket for Sandy Bridge is LGA-1155, and you'll find it paired on motherboards that are themselves based on three new chipsets: the performance-focused P67, the integrated graphics-focused H67 and the entry-level H61. In a nutshell, this means you'll need to buy a new motherboard if you're looking to upgrade your CPU to a 2nd Generation Core.

One of the biggest changes introduced by Sandy Bridge is the integration of a graphics processing unit (GPU) directly onto the die of the processor. In other words, if you're a typical PC user and not a dedicated gamer, there's no need to connect a graphics card to the CPU. Eliminating that hop between the two chips saves on heat and power loss.

If Intel is to be believed, the new execution units present in its Sandy Bridge GPU can provide more than 20 times the power of Intel's Generation-5 graphics. It will also be able to compete with entry-level discrete graphics cards from Nvidia and AMD.

"The Sandy Bridge family will include a new 'ring' architecture that allows the built-in processor graphics engine to share resources such as cache, or a memory reservoir, with the processor's core", explains Intel. "[This] increases a device's computing and graphics performance while maintaining energy efficiency."

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Neighbour to the GPU is an upgraded video processing unit that dedicates actual silicon to encoding and decoding videos, improving the performance of both. (A demo at this year's Intel Developer Forum featured a three-minute 1080p source video converted to a 640x360 iPhone video in around 14 seconds — or roughly 400 frames per second.)

When it comes to video and photo editing, users can expect a speed increase of up to 50 per cent (compared to Intel's previous generation of chips).

The Sandy Bridge chips will be the first to include Intel's Advanced Vector Extension instructions (AVX), a technology aimed at intensive computing which makes video, image and audio processing speedier with improved colour and image clarity.

In essence, AVX's 256-bit vectors will allow your system to crunch more data by grouping it together in larger chunks. And that directly correlates to the power efficiency of the chip itself. In order to actually benefit from AVX however, consumers will have to be running Windows 7 SP1. (Expect to see the update hit sometime in the first quarter of 2011.)

Hyper-Threading is still present; this is the process by which one physical CPU core is split into two virtual CPU cores. Turbo Boost is back as well, but it's been kicked up a notch from Nehalem's designs.

So in summary, Sandy Bridge includes processing cores, a memory controller, cache subsystem and Intel's sixth-generation graphics processing core -- all on one chip.

Sandy Bridge: Overclocking

Not only can all four cores receive an automatic overclock depending on your system's workload, but the CPU will actually push past the rated thermal design power (TDP) of the chip itself for brief periods of time. The technological wisdom is that a CPU can get away with a bit of over-overclocking before it has to back off at the TDP limit — the CPU doesn't immediately jump up to said limit, for example, if the cores get clocked up to extreme amounts.

Sandy Bridge: Products and nomenclature

Support for Intel's new Sandy Bridge processors has been strong. At this year's CES, Asus and Sapphire revealed new Intel motherboard that use the Sandy Bridge processors (P8P67 and Pure Black P67 Hydra, respectively). MSI is also on the Sandy Bridge bandwagon, with 11 motherboards and 16 notebooks already announced.

The Sandy Bridge processor range will come in two- and four-core variants initially, with six-core and eight-core options to appear in the future.

Note that Intel hasn't dropped the ‘Core' designation from its CPU lineup (Sandy Bridge is just the codename). You'll still see Core i3, i5, and i7 branded chips in the marketplace: a '2' will indicate that the chip is part of the new generation.

Three more numbers will indicate the specific processor SKU. A letter appended to the end (K, S, or T) will detail whether the CPU is unlocked for overclocking, optimised for "lifestyle" computing, or optimised for power-savings.

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AMD Fusion

After years of demonstrations and lengthy delays, Advanced Micro Devices has finally started shipping Fusion APU (Accelerated Processing Unit) processors for netbooks, laptops and small form factor desktops PCs; priced between US$200 and $599.

Unlike Intel's Sandy Bridge family, the first batch of Fusion CPUs are aimed at mainstream PCs, all-purpose laptops and netbooks, with an emphasis on power efficiency. "Intel is starting at the high end, high price, low-volume segments of the market", explains John Taylor, AMD's director of client and software product marketing. "[This is] the segment of the market where discrete graphics processors are prevalent today."

AMD Fusion: What's inside?

The Fusion chips combine a CPU and graphics processor in a single piece of silicon, which helps graphics and programs run a lot faster. On some chips, the integrated graphics processor will allow users to view Blu-ray movies or play 3D games. It will also work in tandem with the CPU to execute data-intensive tasks faster.

According to AMD, Fusion chips offer better graphics performance than Intel's competing Atom chips, which are currently found in most netbooks. Fusion's integrated graphics processors are capable of playing 1080p high-definition video, while Intel's Atom chips, which also integrate graphics processors, are capable of rendering up to 720p video.

Fusion will also speed up processing in notebooks by harnessing the computing power of CPU and graphics cores. The graphics processors will accelerate specific video and graphics tasks such as Flash and DVD video playback, freeing up CPUs for everyday tasks like antivirus and word processing. The graphics processor in Fusion will natively support Microsoft's DirectX 11 technology, which should bring improved graphics and application performance to notebooks.

Until now, PC makers attached a separate chip in netbooks to render high-definition video, which drained battery life. The integrated graphics processors in Fusion chips, which are highly power-efficient, should help eliminate this problem.

Fusion APU chips will also make use of AMD's 'core power gating' technology. This disconnects power to an inactive core, helping to reduce overall power consumption and extending the battery life of notebooks. The company has also included technology that measures power digitally, providing more consistent accuracy than the earlier analog readings.

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AMD Fusion: Products

The Fusion line-up includes the E-350 dual-core chip running at 1.6GHz, which draws 18 Watts of power and is targeted at PCs in the higher price bands. The C-50 is a dual-core chip running at 1GHz: it draws 9W of power and is targeted at PCs in the lower price bands. The chips include CPUs based on the Bobcat architecture.

AMD plans to start shipping the next Fusion chip, code-named Llano, for mainstream notebooks and desktops in the middle of this year. In 2012, the company will also release new Fusion chips with up to four cores for tablets and netbooks. The chips, code-named Wichita and Krishna, will be based on an updated version of the Bobcat CPU core.

Companies including Hewlett-Packard and Lenovo have already started shipping netbooks and desktops with Fusion chips onboard. More PCs based on Fusion were announced at CES 2011, which was held in Las Vegas between January 6 and 9.

HP is launching the Fusion Pavilion DM1 notebook this month. Priced starting at US$449, the lightweight laptop has an 11.6in screen and can play 1080p video. HP has measured DM1's battery life at around 10.5 hours, and high-definition video would shave just a few hours off that.

Lenovo has announced the ThinkPad X120e ultraportable laptop, which has an 11in display and runs on AMD's Fusion chips. The laptop is 65 per cent faster when it comes to graphics and offers 30 percent longer battery life compared to its predecessor, the X100e, which is available with AMD's Neo netbook processors.

"[Fusion] gives users an enhanced experience because the CPU and GPU are on the same chip", said Luis Hernandez, executive director of the Thinkpad transactional business at Lenovo.

The ThinkPad X120e will start shipping in February for under US$400.

Additional reporting by Agam Shah and Tony Bradley.

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