Intel's 22nm Atom: Silvermont, Bay Trail Debut

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This news has been a long time coming. It's been six years since Intel first began talking about Atom. When it was initially announced, the 45nm, in-order core, based on the Bonnell microarchitecture, was a new product from the ground up. It drew on Intel's expertise in other areas and shared some design elements with the original Pentium, but Atom was its own unique design. And for more than half a decade, Intel has kept that same design.

Let's put that in perspective. In the desktop world, we were talking about Windows Vista, Core 2 Duo, and AMD's original Phenom. The Phenom II "Shanghai" refresh was still nine months away, Hector Ruiz was still CEO of AMD. In smartphones, the Cortex-A8 -- the first modern smartphone processor and the chip at the heart of Apple's iPhone 3GS -- hadn't shipped yet. Nokia and RIM were major powerhouses in the cell phone industry and Windows Mobile's market share was still north of 35%. I was thinner, and had more hair.

For the past five years -- and it'll have been nearly six years by the time these new Atom CPUs come to market -- Intel has focused on improving power consumption, improving power consumption, and improving power consumption. Dual-core variants appeared on the desktop in fairly short order, and clock speed nudges have only bumped performance slightly higher. On the one hand, this has paid off tremendously. As someone who spent several weeks with an Intel-powered Gingerbread phone, I can honestly say that yes, you can put an Intel smartphone in your pocket, it works just fine, and battery life is decent.

But there's no hiding the fact that Atom is getting long in the tooth. AMD's Brazos outperformed it decisively in 2011 and with Kabini (second-gen Brazos) and the Cortex-A15 both coming to market, Intel has finally given Atom the re-architecting it deserved.

Code Names:

Here's the various parts:
  • Avoton -- Low power SoC, aimed at servers. Follow-up to Centerton, will debut later this year.
  • Rangely - For comms, infrastructure products.
  • Bay Trail - Tablets. First quad-core Atom, targeting holidays, 2013. Also in some ultramobiles.
  • Merrifield -- Follow-up to Medfield. Shipping by end of year to meet Q1 2014 launches.

Behold Bay Trail:

This new Atom is an out-of-order processor, but many of the basic blocks are identical to what we saw in Silvermont. Intel stuck with a dual-issue design with relatively limited integer and floating point pipelines. There are, however, a significant number of improvements.



Execution units have been redesigned for more efficient, lower-latency operation. The L2 cache has expanded and is now shared between cores. Intel isn't using Hyper-Threading this time around, opting instead to go for a straight 1:1 relationship between threads and core count. Many of the most significant changes to Atom's core for Silvermont are focused on how the chip handles floating-point code. x87 FPU code running on Atom was pretty slow, partly by design, and partly thanks to a CPU bug that inserted a cycle of latency in between any two consecutive x87 operations. CPU analyst Agner Fog describes the problem as follows:

Whenever there are two consecutive x87 instructions, the two instructions fail to pair and instead cause an extra delay of one clock cycle. This gives a throughput of only one instruction every two clock cycles, while a similar code using XMM registers would have a maximum throughput of two instructions per clock cycle.
While latencies and throughput varied depending on the type of operation, Atom's x87 latencies and instruction throughputs were disappointing. We can't give you an exact breakdown of how Silvermont improves on this situation yet, but we've seen that data. The improvements are substantial and non-trivial. Silvermont's latencies for various x87 operations are often half of Saltwell's, with certain instructions outputting more than twice as often.

Even with these improvements, Atom will never be a heavy-lifting core, but it should handle a great deal of legacy code more gracefully than it currently does.



Bay Trail / Avoton cores are deployed in groups of two, called "modules", but this system has more in common with ARM processors than with AMD's Bulldozer modules. Each of the two cores on a Bay Trail module is a complete core, with a shared L2 cache. As you'd expect, multiple modules can be linked together to build out the system.
 

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Interesting. The proof will be, as mentioned, in the product shipped, but does AMD get a head start, then compete on price?

For some reason, I've never had a comp with AMD. Am I a snob? :-)

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AMD will retain their price advantage against Intel's higher end products but the ATOM SoCs are pushing to be competitive with ARM and that's below what AMD can go yet...

Besides, AMD's still targeting the performance range between ATOM and Core i-Series... Even Temash, which is the new 28nm SoC APU that's primarily intended for tablets has a Turbo Mode feature for the quad core version that more than doubles its max TDP from 5.9W to 14W (CPU clock speed ramps up from 1GHz to 1.4GHz)... Meaning it can basically switch from mobile to low end Ultrabook performance.

Though, Turbo Mode requires an additional battery in the dock to provide enough power without taking a big hit in run time and additional fans to boost cooling while operating in that mode... at least for Hybrids as Temash will also go into laptops...

Main problem for AMD is despite making some good improvements in their power management and reaching pretty low idling power states... They're still not in the same league as ARM and ATOM SoCs...

Like even Haswell will be able to idle to lower power states than Temash... The APU alone can only idle down to about 0.75W but Haswell can go down to about 0.1W... Though that's far better than Ivy Bridge, which can only idle down to about 3W... but still much higher than either ARM or ATOM can go down to...  At least for the SoCs... there are of course other variable like how much power the rest of the system may use...

However, AMD also won't support advance mobile features like always connected standby... So, while they may get into tablets and offer more performance than even Bay Trail... they won't be as mobile a solution, but you could consider them instead of Haswell if don't quite need that much CPU performance and the run times should still be better than today's Ultrabooks with either Temash or Kabini under the hood...

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I hane an Atom based tablet. Performance wise it sounds like it would match my five or six year old laptop, but realistically, it doesn't. Mostly because it only has two gigs of ram, a joke when running anything even slightly modern.

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Bay Trail promises to more than double performance, and it likely will because they're basically cramming 5 years worth of upgrades all at once... Present ATOM is still based on the same architecture as when it was first introduced over 5 years ago.

While, regardless, RAM will be less of a issue because Bay Trail will support up to 8GB and pushes full 64bit support... It'll just be up to the OEMs how much they will offer and being a SoC it may not be possible to upgrade the RAM after purchase... So just make sure of configuration before purchase...

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Did anybody realise that Intel never said whose gpu this Bay Trial , it will use ?. If it uses Imagineering PVR 554MP3, that will ramp the power up a few watts and would need drastic power management. Unless they are targetting large 10 inch tablets, I do not see this chip being successful in tablets. Maybe in microServers where Arm was going to attack, this chip might claw back the market for Intel. For high-end Smartphones, one has to see the total pakage of Intel to judge its potential threat to S600, S800, T4 and T4i chips and whatever else that may come from the other smaller players.

It is also known that Intel's SoC parts are high priced, so that might just restrict the market somewhat. Everyone seems to think that if Intel had a product that could kill ARM, it would do so quickly. I bet to differ from that thinking becuase Intel is "more sly than a fox" and gradually attack se;ected markets of their choosing. They have the luxury of time and huge cash reserves (plus huge fab capacities) so they will play it for maximum effect to them and only them. No one else becuase everything else does not matter to Intel.

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Actually, Bay Trail will be using a GMA based on the Ivy Bridge HD4000... not all the specs are known, like how fast it will be clocked, but it will be scaled back from the 16 execution units that the HD 4000 has to just 4 but it's suppose to still deliver around 3x the performance of the present Clover Trail GMA, which uses a SGX545 at 533MHz.

If true then performance would basically catch the ATOM GMA up to the performance range of AMD's original Brazos/Fusion series.

Since the present Clover Trail GMA is already nearly 3x better than the old Pine Trail ATOM GMA 3150, which AMD Brazos/Fusion offered 5x to 9x better graphical performance... So another 3x boost should put the ATOM GMA up to that level... you still won't be able to play any high end modern games but older games like WoW, Starcraft 2, etc should finally be playable... and full HD resolution screens should be no problem as it will definitely support up to 2560x1600 resolution.

They're also reportedly pushing some other Intel features like QuickSync, so with the right apps you could possibly do some video editing that won't take forever to do.

What may be more important though is the fact Intel supports Linux drivers for their own GMA and driver support for the HD 4000 has improves since it was first released and that should translate over for the Bay Trail GMA for a better launch driver performance and reliability...

Along with 64bit support should make a lot more options available to Bay Trail than is available to the present Clover Trail.

Anandtech did a analysis on what's known so far about Bay Trail and noted that part of the architectural improvements being reported that Bay Trail should be able to prioritize resources between CPU and GPU and the GPU can be prioritized as needed to help max out performance.

Along with a more basic version of Intel's Turbo Boost technology, something akin to how it worked for Sandy Bridge, and is called Burst Mode for Bay Trail...

All the while Bay Trail is also suppose to improve power efficiency... though that remains to be seen but Clover Trail already manages to beat Cortex A9 ARM SoCs like Tegra 3 for power efficiency. So battery life should be good despite the performance increase...

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