Unified Zen4 Architecture AMD’s small and large cores are completely different to Intel’s.

Intel's 12th/13th generation cores use a hybrid architecture of large and small cores, and AMD is finally following suit, but not in the same way.

After the samples were revealed, AMD confirmed in an official programming guide that the AMD Family 19h Model 70h processor has both high performance and low power core designs.

Unsurprisingly, this refers to the next generation of mobile notebook platforms, codenamed "Pheonix 2", or the APU fusion design.

According to the latest exposure, the Pheonix 2 engineering sample is designed with a single CCX/CCD chip, integrating 2 high performance cores and 4 low power cores, forming 6 cores and 12 threads.

The large cores range from 4.0-5.0GHz, averaging around 4.2-4.3GHz, while the small cores range from 2.5-4.0GHz, averaging just under 3.0GHz and occasionally reaching 4.0GHz.

The power consumption of the whole SoC is only around 15-20W, with two large cores at 7-8W and four small cores at around 5W, all very low, but it is not clear whether this is the daily average power consumption or the maximum and peak power consumption.

Of course, the above is just for this sample, and as usual the final product will be much higher in frequency.

It is worth noting that Intel's large and small cores are based on completely different architectures, with the large cores coming from the Core family and the small cores from the Atom family, the advantage being that the latter are more power efficient, but because of the different architectures the specifications cannot be unified, for example the AVX-512 instruction set can no longer be enabled, the small cores do not have hyperthreading and scheduling assignments are more troublesome.

AMD's large and small cores are both unified with the Zen4 architecture, where the large core is the full standard version and the small core only optimises some of the cache, lowers the frequency and may have some other details to simplify, but the core architecture is exactly the same.

This can reduce power consumption and improve energy efficiency, and maintain overall consistency, especially for easier scheduling of systems and applications.

As for the aforementioned large-core Zen4 and small-core Zen4c, these have always been rumours and have not been officially confirmed, and the Zen4c claim is precisely a conjecture based on the streamlined (compact) version.

The Zen4c does exist, of course, but the only known product is Skylar's 'Bergamo' range of servers and datacentres, officially due in the first half of this year, with up to 128 cores and 256 threads.

According to previous claims, the Pheonix 2 has two Zen4 cores with integrated 2MB L2 cache and 4MB Level 3 cache, and four Zen4c cores with integrated 4MB L2 cache and 4MB Level 3 cache, which still equates to 1MB L2 cache per core without any streamlining, just less Level 3 cache.

There is also a GPU core for the RDNA3 architecture with up to 8 CU units (512 stream processors), a third less than the Raider 7040HS series, and memory support for DDR5 and LPDDR5.

AMD Pheonix 2 is expected to be released later this year to take on Intel Meteor Lake 14th generation Core, which will introduce the Intel 4 process, Chiplet small chip design and new CPU/GPU architecture for the first time.