AMD's Upcoming Phoenix CPUs to Feature Hybrid Design: Document

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Zen 4 and Zen 4c cores?

AMD
(Image credit: AMD)

AMD's upcoming codenamed Phoenix accelerated processing units (APUs) are set to feature a so-called hybrid design containing both high-performance Zen 4 cores and  energy-efficient Zen 4c cores, according to an AMD's processor programming guide discovered by InstLatX64.

AMD's processor programming guide clearly points to Performance Cores marked at 01h and Efficiency Cores descripted as 1h, an evident indicator that AMD's upcoming processor will feature two types of general-purpose cores. Given the timing, we believe that we are dealing with AMD's codenamed Phoenix processor featuring Zen 4 and Zen 4 cores, but keep in mind that AMD calls them otherwise.

The document sheds some light on how AMD's hybrid Big.Little-like design will work. Just as earlier AMD's documents pointed out, the company's high-performance and energy-efficient cores feature a different feature set. Therefore, software makers are advised to design their programs accordingly. 

"Read-only. Reset: Fixed,Xh. Defines per-core architectural feature differentiation (microarchitectural resources, etc.) that may lead to a different performance, core clock boost, and power characteristic," a statement in the AMD PPR reads.

(Image credit: InstLatX64/Twitter)

Of course, a hybrid CPU design will make AMD's offerings more competitive with Intel's Alder Lake and Raptor Lake products in the laptop CPU market. Usage of a hybrid design containing both high-performance and high-efficiency cores will enable AMD to hit performance levels at wattages not attainable today. Meanwhile efficient usage of low-power cores depends on software in general and operating system in particular. 

When we reported about AMD's alleged Phoenix 2 processor with a hybrid design a week ago, it left us wondering why would AMD use the same — Phoenix APU — codename for completely distinctive processors. Apparently, these CPUs are not that different as, according to AMD's programing guide, they both feature a Big.Little-like design.

Anyhow, AMD's codenamed Phoenix processors are expected to hit the market this year, so expect independent tests of these units at Tom's Hardware.

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Anton Shilov
Anton Shilov
Contributing Writer

Anton Shilov is a contributing writer at Tom’s Hardware. Over the past couple of decades, he has covered everything from CPUs and GPUs to supercomputers and from modern process technologies and latest fab tools to high-tech industry trends.

29 Comments Comment from the forums
  • 1_rick
    "Performance Cores marked at 01h and Efficiency Cores descripted as 1h"

    Wat.
    Reply
  • ezst036
    Both of the major x86 CPU companies embracing big.little will likely forestall an ARM/RISC-V future for a while.
    Reply
  • AgentBirdnest
    1_rick said:
    "Performance Cores marked at 01h and Efficiency Cores descripted as 1h"

    Wat.
    Also, the very next sentence:
    "we are dealing with AMD's codenamed Phoenix processor featuring Zen 4 and Zen 4 cores, but keep in mind that AMD calls them otherwise. "

    Umm...
    Reply
  • 1_rick
    AgentBirdnest said:
    Umm...

    LOL!

    Well, the screenshot below shows the numbers are 0h and 1h, so that's just a typo. And the sentence you quoted should've said "Zen and Zen C", and, funnily enough, that's how I read it. I had to go back to check to see that it was wrong.

    Edit: actually, the previous paragraph correctly says "these are probably Zen 4 and Zen 4 c", so the entire sentence in the second paragraph is redundant, but that's the state of journalism today, now that all the copy editors have been fired.
    Reply
  • bit_user
    ezst036 said:
    Both of the major x86 CPU companies embracing big.little will likely forestall an ARM/RISC-V future for a while.
    Yeah, I think the author is wrong in saying this was about competing with Alder Lake. Phoenix is a N4 port of Zen 4 and should have no problem out-performing current Intel in laptops of comparable wattage, even with all big Zen 4 cores.

    IMO, this is about two things (and I'm not sure which is the bigger concern for them):
    Meteor Lake, scheduled to launch by the end of the year on the new Intel 4 node.
    ARM-based laptops, powered by Qualcomm and Mediatek.Apple could factor in, as well. I'm pretty sure it's a tertiary concern, since I think there aren't a lot of people switching to Apple at any given time, but it's got to be an ongoing concern for everyone in the PC ecosystem.
    Reply
  • ezst036
    bit_user said:
    Apple could factor in, as well. I'm pretty sure it's a tertiary concern, since I think there aren't a lot of people switching to Apple at any given time, but it's got to be an ongoing concern for everyone in the PC ecosystem.

    Apple is coming up a lot more than people realize, as is Linux. https://gs.statcounter.com/os-market-share/desktop/worldwide
    Microsoft doesn't command the 95% marketshare that they used to some time ago. Give it another year or two and Windows may not even be above 70%. When Windows does go below 70%, it makes me contemplate how that will force the market as a whole to shift.
    Reply
  • bit_user
    ezst036 said:
    Apple is coming up a lot more than people realize, as is Linux. https://gs.statcounter.com/os-market-share/desktop/worldwide
    Microsoft doesn't command the 95% marketshare that they used to some time ago. Give it another year or two and Windows may not even be above 70%. When Windows does go below 70%, it makes me contemplate how that will force the market as a whole to shift.
    Cool chart. Doesn't say what's their data source, however. So, I take it with a grain of salt. For one thing, it's awfully suspicious the way Unknown fluctuates by almost a factor of 2, over a period of just a few months.

    Note that ChromeOS and Unknown are also continuing to gain adoption - it's not only MacOS.

    As this represents "Worldwide" usage, a lot of the fleeing from Windows will be in certain notable countries pushing to develop their own alternatives. They're certainly not going to jump on the MacOS bandwagon.

    BTW, I assume ReactOS is classified as "Unknown". I used to be interested in it, but considering where most of the development seems to be happening, I think I'll stick to WINE on Linux, if I need to run any Windows programs.
    Reply
  • salgado18
    bit_user said:
    Cool chart. Doesn't say what's their data source, however. So, I take it with a grain of salt. For one thing, it's awfully suspicious the way Unknown fluctuates by almost a factor of 2, over a period of just a few months.

    Note that ChromeOS and Unknown are also continuing to gain adoption - it's not only MacOS.

    As this represents "Worldwide" usage, a lot of the fleeing from Windows will be in certain notable countries pushing to develop their own alternatives. They're certainly not going to jump on the MacOS bandwagon.

    BTW, I assume ReactOS is classified as "Unknown". I used to be interested in it, but considering where most of the development seems to be happening, I think I'll stick to WINE on Linux, if I need to run any Windows programs.
    Actually, if you view the entire historic data since 2009, Windows is in a constant decline, and the biggest factor for that seems to be OS X. Linux and Chrome OS did grow a little too, but by a very small amount.

    Reply
  • Kamen Rider Blade
    1_rick said:
    LOL!

    Well, the screenshot below shows the numbers are 0h and 1h, so that's just a typo. And the sentence you quoted should've said "Zen and Zen C", and, funnily enough, that's how I read it. I had to go back to check to see that it was wrong.

    Edit: actually, the previous paragraph correctly says "these are probably Zen 4 and Zen 4 c", so the entire sentence in the second paragraph is redundant, but that's the state of journalism today, now that all the copy editors have been fired.
    Zen #C cores are just LapTop cores moved onto DeskTop/Server for usage with tunning for efficiency given the higher power/thermal budgets that the new platform allows.

    The P-Core & E-Core label that started with ARM's big.LITTLE is just being re-used for ease of understanding by both Intel & AMD.

    P-Core = Regular die area size Zen # core optimized for Maximum Performance.
    E-Core = LapTop die area size Zen #C cores optimized for Energy Efficiency and Low Power.
    Reply
  • ottonis
    It's a good thing that AMD is embracing the big.LITTLE architecture with their upcoming generation of desktop CPUs.
    In order for this concept to be effective, AMD will need some sort of analogon to the Intel thread director that will distribute computing load across different cores in the most sensible way. This includes a close collaboration with Microsoft and Linux in order to optimize their thread directors at the OS level.
    Reply