The upcoming AMD Ryzen CPUs are likely due for a February release and represent the first flush of the red team’s Zen processor architecture. They’re also the first all-new CPUs AMD have released in many a year and, if the early benchmarks and demos are to be believed, could well deliver genuine competition to Intel’s gaming CPU dominance.
The new Zen architecture could change the CPU landscape when it launches this year, but right now these are the best CPUs for gaming.
AMD have given us some tantalising glimpses at the Zen architecture powering the first AMD Ryzen CPUs, first at the Hot Chips symposium and then their own New Horizon event late last year.
But do you know your branch prediction from your retire queue? Your FP register file from your integer physical register file? Nope, us neither, but here's what the new AMD Zen architecture will mean for their next generation of processor and potentially for your next gaming PC.
In short, the AMD Zen CPU architecture represents the best chance for the red team to close the gap on Intel, offering PC gamers a genuine performance processor alternative for our desktop rigs.
If you want to jump right to the good stuff click on the quick links below to get there.
This is the one thing which has remained as clear as thermal paste; exactly when we’re likely to see AMD Ryzen CPUs on the shelves and in our machines. AMD have long said that we’d see the first eight-core, 16-thread Ryzen CPU released in early 2017, with an official launch before the end of Q1.
The end of Q1 generally means the end of March, and AMD reps have said that the launch won’t held back until the very last day of Q1 which would make the Ryzen release very soon. Recent rumours have pointed to a launch just before the Game Developer Conference (GDC) running from February 27 to March 3, as there is a session in the catalogue entitled ‘Optimizing for AMD Ryzen CPU (Presented by AMD)’.
In the GDC session description it originally framed it as an introduction to ‘the recently-launched AMD Ryzen CPU’ though now the ‘recently-launched’ part has been removed.
I doubt this means a Ryzen launch at GDC (though I am expecting others to unveil silicon there) but would indicate that a February release timeframe seems pretty likely.
The main goal for the upcoming AMD Zen CPUs is to offer a credible alternative to the Intel hegemony existing around high-end processors right now, and they absolutely have to be priced accordingly.
Early estimates suggest the Zen architecture will compete with - but probably won't perform faster than - Intel’s current Skylake range of processors when it comes to single-threaded performance. That leads me to believe AMD will continue to price their Zen FX chips lower than the core-comparable Intel parts.
Current rumours have the Zen processors arriving in three distinct tiers - SR 7, SR 5 and SR 3 - following Intel's Core i7, i5, i3 structure. The top SR (Summit Ridge, innit?) tier will be the eight-core, 16-thread CPUs, and we're being told to expect the highest clocked version to retail for around $500 with a slightly slower octo-core costing around the $350 mark.
That's an impressively low initial price if that's in any way true, with the cut-price eight-core chip being a great way of offering an incentive to people on an old Core i5 looking for an upgrade.
I’d also expect to see similar pricing between the Core i5-6600K and the quad-core, eight-thread variant of the AMD Summit Ridge range. At the moment that would mean a price of around $250 (£215). It looks like AMD will again be betting on an increased thread count to tip the balance against Intel chips which will still have a higher straightline speed.
AMD have then gone back to the drawing board for their new x86 AMD processor architecture with Zen offering the promise of clawing back performance, and potentially market share, from their big blue Intel rivals. This time though their new CPU design represents more of a balancing act; nailing improved single-core throughput for existing game engines as well as catering to the multi-threaded approach newer graphics APIs, like DirectX 12 and Vulkan, are finally offering.
AMD’s CEO, Lisa Su, introduced the ‘guts of Ryzen’ at the New Horizon event in December, detailing the five key new features that make it the fastest processors architecture they’ve ever created. The five new features in question are: Neural Net Prediction, Smart Prefetch, Pure Power, Precision Boost and Extended Frequency Range. Altogether they’re known as AMD SenseMI Technology.
These allow the Ryzen CPU to “sense and adapt to its environment, which makes it an extremely intelligent processor, capable of learning on the fly.” According to Su that gives the Ryzen silicon ‘true machine intelligence’ which accounts for around 25% of the performance uplift the Zen architecture is promising over its forebears.
The Neural Net Prediction part of the chip allows it to self train and preload the right instructions to run faster. Once it figures out what the right instructions are the Smart Prefetch feature learns to anticipate the data an app needs and aims to have it ready before it’s actually needed.
The Ryzen processors also house hundreds of sensors to track and locally optimise the silicon to enable it to run at its fastest while still maintaining the lowest possible power draw. These sensors feed into the Pure Power and Precision Boost features, which deliver a huge amount of control to the CPU itself.
Pure Power and Precision Boost work together to “dial up the frequency and dial down the power on each part of the chip, independently, in milliseconds.” This performance optimisation is aimed at making the changes to power and frequency as quickly and as unobtrusively as possible.
This was something AMD’s Mike Clark, Zen’s lead architect, spoke about before. “We had the power focus from the beginning of the project. We do aggressive clock gating with multi-level regions to make sure we’re gating off logic when we’re not using it."
The final piece of the SenseMI puzzle is the Extended Frequency Range. This is essentially analogous to the GPU boost you get on the latest Nvidia graphics cards where the upper limits of the clockspeed aren’t rigidly defined parameters but are almost entirely based on the thermal performance of the machine’s cooling setup. If you’re rocking liquid cooling you’ll get a higher upper limit to the operating frequency of your Ryzen CPU.
It’s a fully automated solution and basically allows for processor overclocking without any user input outside of deciding what cooling to drop onto their chip. It looks like this is going to be a feature of all the Ryzen processors, which makes sense given AMD have confirmed that there’s going to be no locked multipliers on any of their new CPUs, opening them all up to overclocking - should you have the right motherboard anyway.
Outside of the new features there are some silicon advances which are also delivering performance boosts to the new Zen architecture. Before last year's Hot Chips symposium in Silicon Valley AMD gave us a sneak peak at what's under the Zen hood, and it's a mighty complex beast. Mike Clark, the lead architect on the Zen x86 core, took us through a deep dive on the heart of the new microarchitecture detailing exactly how they managed to nail their target of a 40% instructions per clock increase over their last generation of processor.
“We’ve taken a brand new core engine - tuned for performance - combined it with a high-bandwidth, low-latency cache system," explains Clark. "We've thrown SMT on top of it so we can get high throughput when we need to and the used the new 14nm FinFET technology to also get low-power and scale the design across a number of SoCs from client to servers.”
It's those three pillars of improved core design, better cache and a focus on lower power which have allowed AMD to hit their target. They've been working on the first two for decades, but targeting power contraints normally isn't something that comes until later on in AMD's silicon designs.
"We knew, for this design, we needed to have power analysis going on in the microarchitecture from day one and be choosing the right features to still deliver the IPC increase," says Clark, "but be able to maintain equivalent power to our previous generation."
One of the main things which has given the core engine its boost is the move towards an SMT-based core, giving it an approach to multi-threading which is much closer to Intel's HyperThreading. They've also improved the brand prediction allowing for more instructions to be completed per clock cycle.
"We’re both a wider machine - we can send more instructions into the machine per cycle, 6 vs. 4," says Clark. "And then we’re a deeper machine, meaning we can hold more instructions and we can look further into the program for parallel work that we can execute."
That means the Zen architecture is able to both chew through more processing tasks as well as dig deeper into the queue of tasks it has yet to finish, picking off the ones it can tackle concurrently.
But all that counts for naught if they can't keep the high-performance system fed with data. To do that you need a good cache system and AMD have doubled the bandwidth available to its level one and level 2 cache while improving the level 3 cache bandwidth by five times what was available on its previous cache design.
"The combination of that better core engine and that better cache system allow us to get the 40% IPC uplift, explains Clark.
"Overall we’ve been increasing our power design methodology on the physical design side, all through the ‘Dozer generation," says Clark. "And we were able to leverage all that learning - with new learning - and all that in combination has lead to us being able to achieve the IPC uplift and hold power steady or neutral with the previous generation.”
The initial AMD Ryzen CPU will be the eight-core, 16-thread beast. This is the top-end processor previously known as Summit Ridge, though the Ryzen range of chips will cater for many different budgets and needs.
"Zen, for AMD, is not just one product or two products," explained AMD CEO, Lisa Su. "It's really a family of products that will roll out."
The chief architect for Zen, Mike Clark, echoed his CEO's statement. “Zen is not a destination," he said. "it’s a starting point. AMD is back, but we’re also back to stay. We’re going to continue to push high-performance compute going forward in our next generation - we’re totally committed to high performance compute.”
We’re expecting quad-core parts eventually to go along with the octo-core processors. They will also support Simultaneous Multi-Threading (SMT), a technology analogous to Intel’s HyperThreading, allowing each discrete CPU core to process two threads concurrently.
There are rumours, however, that AMD will be releasing a lower-tier quad-core Ryzen processor without their SMT feature enabled, leaving it as a four-core, four-thread chip. That would make sense given that it looks unlikely that AMD will be making any Ryzen processors with fewer than four cores.
The Zen architecture looks to have been built in four-core complexes, so the octo-core chip will sport a pair of these core complexes, but that might mean unless AMD are able to create half-scale versions we won’t get dual or hex-core options.
It’s a different situation to AMD’s previous architecture in which their Bulldozer CPUs (as well as the later, iterative architectures toting the similarly heavy-plant-based codenames of Piledriver and Excavator) were built using nominally dual-core modules, where each ‘core’ shares an unhealthy chunk of logic between them. The quad-core modules in Zen have discrete logic in each core, sharing only access to the L3 cache.
A quad-core Bulldozer chip uses a dual-module design and an octo-core uses four modules. AMD’s eight-core chips, like the FX-8370, are effectively quad-core CPUs using a slightly hobbled form of HyperThreading. With the Summit Ridge CPUs, on the other hand, each promised Zen core is going to be fully discrete with its very own, jealously-guarded silicon.
In terms of the process AMD is using for its new architecture they are going with the same 14nm FinFET lithography already used in their Polaris-based graphics cards. The FinFET design uses essentially the same Tri-Gate transistor layout Intel has been building into their processors since the 22nm shift for their Ivy Bridge platform. It’s a 3D transistor design used to get around the electrical leakage which occurs in planar transistors when components are shrunk down to such microscopic levels.
In terms of clockspeeds all we know so far is that we’ll be looking at a base of 3.4GHz for the initial Ryzen CPUs. The operating frequencies of the pre-launch engineering samples have been steadily rising as we push towards launch, with the latest F4 stepping looking like a 3.4GHz base and 4GHz turbo configuration.
I wouldn’t be at all surprised if that was the final release clockspeed for the very first AMD Ryzen processors.
In terms of the power draw the octo-core Ryzen is going to be a 95W chip. Their previous eight-core processors came in at 125W, though they also had a couple of 220W CPUs too, but we doubt they'll want to go down that route again with Zen...unless they want to get a 5-6GHz chip out down the line.
But even more interesting on that front is the idle power performance of these engineering samples. They are reported to be able to deliver idle power of just 2.5W and 5W for the quad and octo-core CPUs respectively; both able to scale down their clockspeeds to an operating frequency of just 550MHz.
And we thought the Skylake architecture was impressive when the 6700K showed it could drop down to 800MHz with a 3.5W idle power draw.
In terms of the platform the Zen processors will drop into, AMD is simplifying things by unifying both their CPU and APU sockets. The new AM4 socket will mean that, with a single motherboard, you can be assured of compatibility with all of AMD’s Zen silicon going forward.
There is a much greater pin density on the new socket compared to the outgoing AM3+ design. The last connection had just 942 pins while the AM4 socket offers a full 1331 potential connections. Not all AM4 chips will use the full complement of pins with the Bristol Ridge APUs not needing all the PCIe lanes or memory options on offer.
This does mean the Zen chips are going to look practically identical to existing AMD processors. Speaking as someone who regularly received loose AMD CPUs in barely padded envelopes, the prospect of bent CPU pins is looming large again with Zen.
There are different levels of AM4 motherboard, however, catering for both the high-performance Zen crowd as well as the more mainstream APU guys. There will be three discrete chipsets for the new AMD platform, with the X370 catering for the high-end systems, with their eight-core, 16-thread Zen processors.
The X370 is going to support 'overclocking+' which will bring the deepest level of system control to the Zen platform, while also taking advantage of the touted 36 PCIe 3.0 lanes available in the Summit Ridge processors to deliver full x16 bandwidth to a twin CrossFireX or SLI multi-GPU array.
Below that are going to be the mainstream-oriented B350 and entry-level A320. Broadly speaking the three tiered range ought to be roughly analogous to Intel's Z270, H270 and H110 chipsets for the new Kaby Lake CPU lineup.
The mainstream B350 will still support a slightly lower level of CPU overclocking, but it doesn't look like it will be natively supporting multi-GPU systems at launch. The low-end A320 then is most basic of AM4 chipsets and won't come with either dedicated overclocking or multi-GPU support.
There will also be a range of dedicated AM4 small form factor chipsets; the X300 will cater to the micro machine fans, allowing them to craft powerful rigs with a tiny footprint. There were a whole load of AM4 boards on display out and about at the CES event at the start of the year.
Specs are one thing, but it’s the performance of the Zen CPU architecture that will make or break the new design, and potentially even AMD itself. They’ve tried to be fancy and second guess the future of the PC hardware market before - introducing an affordable, multi-threaded architecture with Bulldozer which was left behind while the rest of the industry stuck resolutely to relying on the performance of a single processing thread.
You may say gaming is more about graphics power these days, and to some extent you would be correct, but the fact remains you’ll get more performance from your graphics card if it’s plumbed into an Intel-based system than an AMD one, no matter who makes your GPU. Sadly AMD CPUs hold back your graphics hardware, which means high-end gaming systems will always steer clear of the red team’s existing processor designs.
But for the new Zen architecture AMD is promising at least a 40% increase in the instructions per clock (IPC) of their new CPUs. It’s this improved IPC which ought to deliver a tangible boost in single-threaded performance, potentially bringing them much closer to the processing speed of Intel’s chips.
The Intel Developer Conference took place mid-August in San Francisco, and AMD was just down the road spoiling the party in a big way. They had an engineering sample of their Zen CPU been running on stage showing it out-rendering an Intel Core i7-6900K and playing Deus Ex: Mankind Divided at 4K.
AMD placed an engineering sample of the Summit Ridge, 8-core, 16-thread Zen CPU up against the similarly-specced Intel Broadwell-E chip and showed their chip outperforming it on a clock-for-clock basis. That's key, as the early Zen engineering samples are running at a relatively low base clockspeed, while the Core i7 6900K is capable of turbo-ing all the way up to 4GHz. The Blender rendering demo had both chips set at 3GHz.
Then at the New Horizon event AMD showed 'the dream gaming PC for 2017 in action' - a mixture of AMD Ryzen CPU and the new Vega GPU architecture, running the new Rogue One DLC for Star Wars Battlefront at over 60fps at 4K. Ooof.
This was the first time the combination of new Ryzen CPU and Vega GPU had been seen running in public, let alone together. Quite the 'one more thing' to round off the New Horizon introduction to AMD's new processor architecture as AMD CEO, Lisa Su, excitedly reminded the crowd there was only one company out there making both high-performance CPUs and GPUs.
Before Vega dropped on the scene though Nvidia did take centre stage alongside the new AMD processor. In a head-to-head Battlefield 1 demo they showed off the new eight-core, 16-thread Ryzen CPU running with the latest GTX Titan X up against an Intel Core i7 6900K using the same Nvidia GPU. Both machines where running at 4K and both with a consistent 60-70fps even when the game was really making with the 'splodes.
Together with the CPU-intensive Blender rendering and Handbrake video encoding demos, showing Ryzen seemingly competing comfortably with the same high-end Intel processor, it paints an incredibly positive picture of where the still unreleased AMD Ryzen CPU is at right now. Being able to compete with Intel's CPU on both the multi-threaded workloads and gaming workloads is incredibly exciting.
And with AMD reps insisting there are still performance optimisations to be made prior to final release things could only get better. Remember, we're talking about a ~$500 AMD processor taking on a $1,000+ Intel CPU here.
If you want to watch the whole New Horizon stream back you can catch it below, starting with the good stuff at the 14.55 mark.
Follow the quick links below to get to the relevant section.