New Turbo Boost

With power in perspective, let’s talk about performance and the lineup. It always made little sense that despite a very competitive microarchitecture, Jaguar both consumed more power and performed worse than Intel’s Silvermont. It turns out that’s more a function of the limited time AMD’s Jaguar team had to bring the design to market. As the basis not only for AMD’s own entry level APUs but also the semi-custom SoCs bids for consoles from Microsoft and Sony, Jaguar had to be done quickly. With Puma+ and its associated SoC designs, AMD could focus more on driving power down and introducing new features, one of which happens to be a very intelligent clock boosting scheme analogous to Intel’s Turbo Boost.

While the bulk of Kabini and Temash silicon ran up to a set maximum frequency, Beema and Mullins SoCs can take advantage of available thermal headroom to increase their maximum frequency for a limited period of time. If we look at the tables below we’ll see this in action:

Mullins vs. Temash - Frequency Gains
  TDP Max CPU Frequency Temash Equivalent Temash Equivalent (TDP) Temash Max CPU Frequency Max Frequency Increase from Mullins
A10 Micro-6700T 4.5W 2.2GHz A6-1450 8W 1.4GHz 57%
A4 Micro-6400T 4.5W 1.6GHz A4-1250 9W 1.0GHz 60%
E1 Micro-6200T 3.95W 1.4GHz A4-1200 3.9W 1.0GHz 40%

AMD no longer reports max non-turbo frequency, unfortunately following in Intel’s footsteps (as well as the rest of the mobile players), but you can assume that they are mostly unchanged from Kabini/Temash. Beema and Mullins can now turbo up to much higher frequencies. In the case of Mullins in particular, since it’s so thermally constrained, the potential upside for frequency scaling is huge.

Beema vs. Kabini - Frequency Gains
  TDP Max CPU Frequency Kabini Equivalent Kabini Equivalent (TDP) Kabini Max CPU Frequency Max Frequency Increase from Beema
A6-6310 15W 2.4GHz A6-5200 25W 2.0GHz 20%
A4-6210 15W 1.8GHz A4-5000 15W 1.5GHz 20%
E2-6110 15W 1.5GHz E2-3000/E1-2500 15W 1.65GHz/1.4GHz -10%/7%
E1-6010 10W 1.35GHz E1-2100 9W 1.0GHz 35%

The frequency gains aren't just limited to the CPU, the 128 GCN cores can also run at higher speeds with Beema and Mullins:

Mullins vs. Temash - GPU Frequency Gains
  TDP Max GPU Frequency Temash Equivalent Temash Equivalent (TDP) Temash Max GPU Frequency Max GPU Frequency Increase from Mullins
A10 Micro-6700T 4.5W 500MHz A6-1450 8W 400MHz 25%
A4 Micro-6400T 4.5W 350MHz A4-1250 9W 300MHz 16%
E1 Micro-6200T 3.95W 300MHz A4-1200 3.9W 225MHz 33%

 

Beema vs. Kabini - GPU Frequency Gains
  TDP Max GPU Frequency Kabini Equivalent Kabini Equivalent (TDP) Kabini Max GPU Frequency Max GPU Frequency Increase from Beema
A6-6310 15W 800MHz A6-5200 25W 600MHz 33%
A4-6210 15W 600MHz A4-5000 15W 500MHz 20%
E2-6110 15W 500MHz E2-3000/E1-2500 15W 450/400MHz 11%/25%
E1-6010 10W 350MHz E1-2100 9W 300MHz 16%

How can AMD hit significantly higher frequencies without a substantial architecture change or new process node? By raising the max thermal operating point of the silicon. Similar to what Intel discovered in architecting its Bay Trail silicon, AMD realized that in ultra portable form factors it would run into a chassis temperature limit before it ever reached the maximum operating temperature of its silicon.

Previously once the silicon temperature hit 60C, AMD would cap max CPU/GPU frequency. However what really matters isn’t if the silicon is running warm but rather if the chassis is running too warm. With Beema and Mullins, AMD increases the silicon temperature limit to around 100C (still within physical limits) but instead relies on the surface temperature of the device to determine when to throttle back the CPU/GPU. In AMD’s own words, this allows the SoC to run at a much higher frequency for up to several minutes before having to scale back down. As long as the physical limits of the die aren’t exceeded, the design remains just as safe as before, but you get better performance.

The real trick is that AMD is able to enable this new chassis temperature governed boost (called Skin Temperature Aware Power Management - STAPM) without requiring any additional sensors or hardware from the OEM. What AMD does instead is gives the OEM tools to properly map SoC temperature to chassis skin temperature. My guess is the OEM runs a set workload, measuring external chassis temperature all while correlating that data with SoC temperature. This mapping will vary on a device by device basis, and obviously won’t be as accurate as having a thermal sensor on the chassis itself, but it’s good enough to get the job done.

AMD claims it’s intelligent about when to boost. The updated power management unit looks at the response to frequency scaling of a given workload and will only boost when the workload will actually benefit from being boosted. This evaluation happens at the hardware instruction level and not at the OS/software layer.

The Lineup

With the exception of compressing the Kabini family into four parts instead of five, AMD kept the same number of SKUs as last year but obviously with updated specs with Beema and Mullins:

AMD Mullins vs. Temash APUs
Model Radeon Brand SDP TDP CPU Cores CPU Clock Speed (Max) L2 Cache Radeon Cores GPU Clock Speed (Max) DDR3 Speed (Max)
A10 Micro-6700T R6 2.8W 4.5W 4 2.2GHz 2MB 128 500MHz 1333
A4 Micro-6400T R3 2.8W 4.5W 4 1.6GHz 2MB 128 350MHz 1333
E1 Micro-6200T R2 2.8W 3.95W 2 1.4GHz 1MB 128 300MHz 1066
A6-1450 HD 8250   8W 4 1.4GHz 2MB 128 400MHz 1066
A4-1250 HD 8210   9W 2 1.0GHz 1MB 128 300MHz 1333
A4-1200 HD 8180   3.9W 2 1.0GHz 1MB 128 225MHz 1066

The Mullins parts get a Micro prefix in front of their model number, implying the SoC's tablet-friendliness. AMD also supplies both TDP and Scenario Design Power (SDP) values for Mullins SoCs, similar to what Intel does with Bay Trail. The latter uses more tablet-like workloads (read: lighter weight) while determining SoC power.

With the exception of the entry level E1 Micro-6200T, TDPs go down substantially with Mullins vs. Temash. Cache sizes and GPU core count remain unchanged, but CPU frequencies and max DRAM frequency supported goes up in many cases.

AMD Beema vs. Kabini APUs
Model Radeon Brand SDP TDP CPU Cores CPU Clock Speed (Max) L2 Cache Radeon Cores GPU Clock Speed (Max) DDR3 Speed (Max)
A6-6310 R4   15W 4 2.4GHz 2MB 128 800MHz 1866
A4-6210 R3   15W 4 1.8GHz 2MB 128 600MHz 1600
E2-6110 R2   15W 4 1.5GHz 2MB 128 500MHz 1600
E1-6010 R2   10W 2 1.35GHz 1MB 128 350MHz 1333
A6-5200 HD 8400   25W 4 2.0GHz 2MB 128 600MHz 1600
A4-5000 HD 8330   15W 4 1.5GHz 2MB 128 500MHz 1600
E2-3000 HD 8280   15W 2 1.65GHz 1MB 128 450MHz 1600
E1-2500 HD 8240   15W 2 1.4GHz 1MB 128 400MHz 1333
E1-2100 HD 8210   9W 2 1.0GHz 1MB 128 300MHz 1333

Beema sees the end of the lone 25W TDP for Kabini, everything is now at 15W or less. The lowest end Beema carries a slightly higher TDP than the entry level Kabini, but otherwise there's more performance at the same TDP across the board. Beema parts don't come with an SDP rating as they're designed for use in more traditional ultrathin notebook PC form factors (presumably running more traditional, read: heavier, workloads).

TrustZone

In 2012 AMD announced that it had signed a license agreement with ARM. Although we’ve since seen AMD announce ARM based Opteron silicon, back then the only official commitment was to ship an x86 SoC in 2013 with an integrated ARM Cortex A5 for TrustZone execution. AMD needed a hardware security platform on its SoCs to remain competitive, and it didn’t have one of its own (Intel’s TXT is proprietary and not a part of what’s licensed to AMD) so ARM’s TrustZone technology was an easy target. To support TrustZone you need an ARM core, and thus AMD committed to integrating a Cortex A5 as a dedicated security processor on some of its 2013 APUs.

Indeed both Kabini and Temash had a Cortex A5 on die, it was simply never enabled due to time constraints. With Beema and Mullins the core is fully functional in what AMD is calling its Platform Security Processor (PSP). AMD will likely publish guidelines on how developers can access and use the PSP, and I’d also expect to see it make its way into other AMD APUs moving forward.

Introduction The Discovery Tablet & Performance
POST A COMMENT

82 Comments

View All Comments

  • superunknown98 - Tuesday, April 29, 2014 - link

    Although I don't think it would happen, or at least be publicly announced, Microsoft could use these new cores in Xbox One but could only enable turbo for the two cores that run the virtualization and Xbox OS. They would also benefit from the reduced TDP, which is something that eventually happens at some point anyway. Reply
  • lmcd - Thursday, May 1, 2014 - link

    Now that comment on the OS and virtualization cores was quite interesting. I now thing that a Puma-edition is likely (though I think a GPU switch-up is more likely if more efficient GCN variants occur. Reply
  • MikeMurphy - Monday, May 26, 2014 - link

    No sense revising an entire chip to save a few watts of power. They might revise it later provided that substantial power savings are attainable, otherwise will implement the usual die shrinks. Minor performance increases shouldn't be ruled out although focus will be on power reduction while maintaining similar performance. Reply
  • Rockmandash12 - Tuesday, April 29, 2014 - link

    And this is what happens when AMD gets into gear and makes a new architecture. Real improvement that's competitive with rivals. Common.... new Desktop flagship architecture that's faster and more efficient? please? Reply
  • Samus - Wednesday, April 30, 2014 - link

    This is pretty impressive. And honestly, out of nowhere. They all the sudden have an amazing tablet/uSFF SoC. Reply
  • silverblue - Tuesday, April 29, 2014 - link

    Didn't Kaveri launch with a fully enabled PSP as well?

    Judging by the performance story thus far, I think it will put to bed the calls for cat cores to replace AMD's higher powered offerings. Yes, we're past K8 performance levels now, but Llano and Trinity (let alone Richland/Kaveri) still have it beat. You'd need some serious clock speeds to get decent performance and it's the wrong silicon for that.

    I was disappointed to see that it's practically the same uarch as Jaguar, meaning we're still going to have a single channel memory controller, however the performance and power improvements are substantial, and the memory controller has been improved anyway which should reduce the need for said controller.
    Reply
  • ET - Tuesday, April 29, 2014 - link

    I think it's hard to draw conclusions of core performance when the RAM is a limitation. It's entirely possible that these cores are still pretty far from the big cores, but on the other hand it's possible that more bandwidth could up performance by quite a few percent. Reply
  • ssnitrousoxide - Tuesday, April 29, 2014 - link

    AMD has always done some impressive work to squeeze every bit of performance from an inferior node. How they managed to improve energy efficiency so much is beyond me. Reply
  • mfoley93 - Wednesday, April 30, 2014 - link

    It seems that most of the power reduction is at the manufacturing level; maybe it's more accurate to engineering tolerances or perhaps a more pure silicon, either way I don't think TSMC will be telling us what it is. The rest comes from eliminating circuitry that provides some more flexibility to OEMs, something nVIDIA has been doing for a couple years now, and while it doesn't really
    count, it's something Apple does very well.
    Reply
  • yannigr - Tuesday, April 29, 2014 - link

    Any idea if Beema will be compatible with existing AM1 motherboards?
    (with only a BIOS update of course)
    Reply

Log in

Don't have an account? Sign up now