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We recently reviewed one of AMD's latest Fusion processors as part of the Asus E35M1-M Pro motherboard. Like Intel's recent Sandy Bridge chips, they combine a programmable graphics engine onto the same piece of silicon as the CPU. It's a modern minor miracle in metal.
Like the first wave of Intel's CPU/GPU hybrids, these initial Fusion chips from AMD cleverly and cautiously avoid underwhelming us by targeting netbooks, where performance expectations are pretty low. For Intel, it was bolting a rudimentary graphics core onto an Atom to create Pinetrail.
AMD's new Bobcat CPU architecture is more forward looking, but by going up against Pinetrail and low-end notebooks, it looks perhaps better than it is.
AMD will follow the trail that has been forged here, though. Over the last 12 months, Intel has moved up the value chain with its CPU-die graphics. Arrandale brought the technology to Core i3 and Core i5 chips, and while the launch of Sandy Bridge at CES may have been spoiled by the swift recall of compatible motherboards, it was still briefly triumphant.
Faster and cheaper than the outgoing Nehalem architecture, Sandy Bridge is eminently suited to heavy lifting tasks that can harness the parallel pipelines of GPUs, such as video and photo-editing. The implications for mobile workstations alone are a little mind numbing, and more than one commentator believes it augurs the death of the discrete graphics card.
The single silicon future isn't quite upon us, however. Without wanting to put a timescale on things, the chances are PC Format readers will still be buying add-in GPUs for a while yet, for one reason and one reason only. Integrated graphics of any sort are and always have been rubbish for gaming.
Fusion and Sandy Bridge may still have that new chip smell about them, but they've been in the public eye for a long time. Fusion was formally announced to the world in 2006, around the same time that AMD purchased graphics firm ATI. Sandy Bridge appeared on Intel's roadmaps a year or so later.
Familiarity should not breed contempt, though. It's hard not to be excited by what is arguably the biggest change to PC architecture for 20-plus years. This new approach to chip design is such a radical rethink of how a computer should be built that AMD has even come up with a new name for it: goodbye CPU, hello Accelerated Processing Unit (APU).
While we wish AMD the best of luck trying to get that new moniker to bed in, it is worth digging around on the company's website for the Fusion launch documents. The marketing has been done very well - the white paper PDF does an excellent job of explaining why putting graphics onto the processor die makes sense, and you can find it in a single click from the front page.
By comparison, Intel's site is more enigmatic and downplays the role of on-die graphics. The assumption seems to be that those who care already know, but most consumers are more interested in the number of cores a chip has.
The next big thing?
That's fair enough: computers are commodities now and a simple 'Intel Inside' has always been the company's best way of building its brand. It also works as a neat way of avoiding hubris.
In the world of PC tech, it's hard to work out what the next big thing will be and what is going to blow.
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The CPU/GPU hybrid seems like a no-brainer, but a lot has changed in graphics since 3dfx first introduced the masses to the 3D video co-processor. It's been 15 years since Voodoo boards began to transform the sprite-based world of PC gaming, and with almost each new generation there's been some new feature that's promised to change the world.
Some of these breakthroughs have been welcome, and rightly gone on to achieve industry standard status. Routines for anti-aliasing, texture filtering and hardware transform and lighting were early candidates for standard adoption, and we now take it for granted that a new GPU will have programmable processors, HD video acceleration and unified shaders.
Other innovations, though, haven't found their way into the canon. At various times we've been promised by graphics vendors that the future lies in technologies that never picked up strong hardware support, such as voxels, tiling, ray tracing and variously outmoded ways of doing shadows.
Then there are those fancy sounding features that seem to have been around forever but still aren't widely used, such as tessellation, ring buses, GPU physics and even multicard graphics.
On a minor - related - note, hands up if you've ever used the digital vibrance slider in your control panel. Thought not.
All of which is not to say that Fusion and Sandy Bridge won't catch on. According to the roadmaps, it's going to be pretty hard to buy a CPU that doesn't have the graphics processor built in by the end of this year.
First-generation Core architecture chips are rapidly vanishing from Intel stockists, while AMD is expected to introduce a mainstream desktop combination chip, codenamed Lano, this summer with a high performance pairing based on the new Bulldozer CPU sometime in 2012.
If you buy a new PC by next spring it'll almost certainly have a hybrid processor at its heart.
There are three big advantages to hybrids. The first is that they're self-evidently very cost effective to manufacture compared to separate chips for the CPU and graphics and all the circuitry between.
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For similar reasons, they also require less power - there are fewer components and interconnects that need a steady flow of electrons, and even on the chip die itself Sandy Bridge and Fusion allow more sharing of resources than last year's Pinetrail and Arrandale forebears, which put graphics and CPU on two separate cores in the same package.
Finally, slapping everything on one piece of silicon improves the performance of the whole by an extra order of magnitude. Latency between the GPU and CPU is reduced - a factor very important for video editing - and both AMD and Intel are extending their CPU-based abilities for automatic overclocking to the GPU part of the wafer too.
It goes without saying that these advantages will only be apparent if you actually use the GPU part of the chip. But you can have the best of both worlds: switchable graphics such as Nvidia's Optimus chipsets are well established in notebooks already, including the MacBook Pro. These flick between integrated and discrete chips depending on whether or not you're gaming, in order to save battery life or increase framerates.
That's not really a technology that will find much footing on the desktop, where the power saving would be rather minimal for the effort involved, but that's not to say there are no opportunities there. A 'silent running' mode using the on-die GPU would be invaluable for media centres and all-in-one PCs, for example.
More importantly for us, once every PC has integrated graphics there's every likelihood that some GPU-friendly routines that are common in games - such as physics - could be moved onto there by default. It'd be better than the currently messy approach towards implementation of hardware acceleration for non-graphics gaming threads.
Can't do it all
That scenario, however, depends on an element of standardisation that may yet be lacking. Sandy Bridge contains an HD 3000 graphics core which, by all accounts, is Intel's best video processor to date.
HD 3000 is very good at encoding and decoding HD video, plus it supports DirectX 10.1 and OpenGL 2.0. That means it can use the GPU part of the core to accelerate programs such as Photoshop, Firefox 4 and some video transcoders too.
The problem is that, as has become almost traditional, Intel is a full generation behind everyone else when it comes to graphics. It's still living in a Vista world, while we're all on Windows 7. Don't even ask about Linux, by the way, as there's no support for Sandy Bridge graphics at all there yet (although both Intel and Linus Torvalds have promised it's coming).
Fusion, by comparison, has a well supported DirectX 11-class graphics chip based on its current Radeon HD6000 architecture. That means it supports the general purpose APIs OpenCL and DirectX Compute. Sandy Bridge doesn't - which may delay take up of these technologies for the time being.
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Conversely, Sandy Bridge does feature the new Advanced Vector Extensions (AVX) to the SSE part of the x86 instruction set. These are designed to speed up applications such as video processing by batching together groups of data, and won't be in AMD chips until Bulldozer arrives later this year.
You'll need Windows 7 SP1 to actually make use of AVX, mind you. But by the time applications that use them appear, most of us will be running that OS revision or later.
Gaming performance
All this is academic if you're just interested in playing games. A quick look at the benchmarks will show you that while the HD 3000 is better than its predecessors for gaming, it's still not much fun unless you're prepared to sacrifice a lot of image quality.
By comparison, the first desktop Fusion chips - codenamed Llano and based on the current K10 architecture - will have more in the way of graphics firepower. But an 80 pipeline Radeon core is still only half the power of AMD's most basic discrete card, the HD6450. We wouldn't recommend one of those, either.
Feedback from games developers we've spoken to has been mixed so far. On the whole, they have broadly welcomed hybrids, and some have gone as far as saying that Sandy Bridge will meet minimum graphics specifications for a number of quite demanding games. Shogun 2 and Operation Flashpoint: Red River are good examples of this.
Ultimately, though, developers are interested in hitting these system requirements because it opens up a large market for their games among laptop owners. As far as innovation goes, the cool kids still code at the cutting edge.
What of the future?
You might be tempted to point out that it's early days yet, and CP-GPU hybrids - for want of a better phrase - are still in their infancy. Give it a couple more years and the discrete graphics business could be dead.
John Carmack himself recently noted that he didn't see any big leaps for the PC's graphical prowess in the near future. That gives combination processors time to catch up, doesn't it?
Well, here are some numbers to convince you otherwise. Moore's Law says the number of transistors that can be cost effectively incorporated inside a chip will double every two years. A four-core Sandy Bridge processor with integrated HD 3000 graphics packs around 995 million transistors. According to Intel's oft-quoted founder, that means that we could expect CPUs in 2013 to boast 2,000 million transistors on a single die.
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Sounds like a lot, until you realise that 2009's Radeon HD5850 already has a transistor count of 2,154 million - which would all have to be squashed onto a CPU die to replicate the performance levels.
By applying Moore's Law, then, it'll be at least 2015 to 2016 before you'll be able to play games at the resolution and quality you were used to 18 months ago. What are the odds of seven-year-old technology being considered more than adequate as an entry level system? Not high, are they?
By that reasoning hybrid processors are going to struggle to ever move up into the 'mainstream' performance class. You see, even though graphics engine development has slowed down considerably in recent years, games are still getting more demanding. Even World of Warcraft needs a fairly hefty system to see it presented at its best these days. Just Cause isn't a spectacular looker, but it can strain a respectable system beyond breaking point if you turn all the graphical settings up and the pretty bits on.
We're also finding new ways to challenge our hardware: multi-monitor gaming is now so common it's included in Valve's Steam Survey. That means higher resolutions and more anti-aliasing, neither of which are cheap in processing terms.
And even if Moore's Law were somehow accelerated so that in five years' time integrated GPUs could be cutting edge, a 4,000 million transistor chip is an enormous undertaking that would be expensive to get wrong. Yields would have to be exceptionally good to make it financially viable - it's a much safer bet to produce separate parts for the top performance class.
What's more, high graphics chips are incredibly different to CPUs in terms of manufacture and operating environment. They're almost mutually exclusive, in fact.
A Core i7, for example, consumes less power and runs much colder than a GeForce GTX570. Could you get the same graphics power without the 100ºC-plus heat? Unlikely.
The tolerance for error is also much lower - if a single pixel is corrupted on screen because the GPU is overheating, no-one notices, but if a CPU repeatedly misses a read/write operation you have a billion dollar recall to take care of.
The GPU is dead
It would be lovely to be proved wrong, though. If a scenario arises where we can get the same sort of performance from a single chip - with all the overclocking features - that we currently enjoy from the traditional mix of discrete GPU and dedicated CPU, then we'd be first in the queue to buy one.
Right now, though, both Nvidia and AMD reported growth in their graphics divisions during 2010, despite the appearance of Intel's Arrandale hybrids early in the year. Perhaps this is the more likely outcome: it's easy to envision a world in, say, a decade or so, when the market for PC 'separates' is similar to the hi-fi one.
Because after a century of miniaturisation and integration there, valve amps are still the apeothesis of style and performance. In other words, a CPU/GPU hybrid chip may be good enough one day, but it won't be the best. And that is what we will always demand.
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