Back at CES 2023, AMD announced its Zen 4 ultraportable CPU lineup, dubbed Ryzen 7040 series. These are Zen 4 CPUs coupled with RDNA3 graphics designed for portable laptops that can also handle gaming. They focus more on efficiency than the company’s fire-breathing Dragon Range CPUs for desktop replacement machines. Now AMD is readying a third batch of mobile chips, and they’ll mark the company’s foray into hybrid APUs with both performance and hybrid cores to boost performance and efficiency. It seems AMD is borrowing Intel’s terminology for the different cores, too.
News of AMD’s plans comes from a document called the Processor Programming Reference (PPR) for AMD’s Phoenix APUs. It was posted to Twitter by @InstLatX64 and flagged by Hothardware.com. It states clearly the APUs include both performance and efficiency cores. It also says that some cores have “better power” (meaning efficiency), and others have more “performance potential.” It remains to be seen if AMD will adopt Intel’s terminology, but we highly doubt it. It’s similar to how Intel uses “tiles” instead of “chiplets” for its upcoming Meteor Lake architecture; they rarely borrow their competitor’s terms. The posted reference guide is for developers, so AMD will likely adopt a different term when it comes to market.
AMD’s approach will reportedly see it using both “big” Zen 4 cores and “little” Zen 4C cores, which is new. However, it will probably be making the two core types more similar to what Intel offers with its latest hybrid approach. Its current Raptor Cove P-Cores are about 3.5 times larger than its Gracemont E-cores. They also run vastly different maximum clocks. On the Core i9-13900K, for example, the P-cores boost to 5.8GHz, with the E-cores topping out at 4.3GHz.
AMD’s Phoenix line of CPUs and APUs focus on efficiency. Credit: AMD
On the other hand, AMD’s Zen 4C cores will reportedly be half the size of their big brothers, sacrificing only a bit of L3 cache and “some frequency,” according to the leak. If true, it could give AMD an advantage over Intel in that the efficiency cores could be much more potent than Intel’s version. It could also make life easier for developers, as they won’t have to differentiate between the two cores as much. AMD also plans to use Zen 4C cores in its upcoming Bergamo “cloud native” CPUs featuring 128 Zen 4C cores with 256 threads.
We don’t doubt this “leak” is real, as it’s a sensible approach to a mobile platform and one that AMD has never ruled out. Back in 2020, AMD’s CTO said it wouldn’t talk about future plans but would only go hybrid if it wasn’t just for marketing. In other words, it wasn’t just going to stuff a chip full of tiny cores to boast about core counts. However, a year later, the company filed a patent for an x86 hybrid design, showing it’s been considering this approach for some time now. We’ll have to wait for official word from AMD on its Phoenix “hybrid” APUs, as nothing has been officially announced.