AMD Confirms Hybrid Ryzen 3 7440U Phoenix APU With Zen 4 & Zen 4C Cores

AMD seems to have confirmed that its Ryzen 7040 "Phoenix" APUs come in hybrid flavors featuring Zen 4 and Zen 4C cores.

Talking to XDA-Developers, AMD confirmed the existence of a second Phoenix SKU powering its Ryzen 7040 APU lineup. While original Phoenix chips are based entirely on the Zen 4 and RDNA 3 graphics architecture, the second Phoenix SKU, also known as Phoenix 2, makes use of a hybrid Zen 4 + Zen 4C combination for the CPU cores.

As per the confirmed information, the AMD Phoenix 2 Hybrid APUs will feature a dual-core Zen 4 and quad-core Zen 4C implementation on the same CPU die and the RDNA 3 graphics cores for its iGPU. The first APU to make use of such a configuration has also been confirmed to be the Ryzen 3 7440U which will feature 6 cores and 12 threads. The chip will also be available in the standard Zen 4-only variation which would allow AMD to dual-source the production based on demand for these chips.

In my correspondence with AMD, several key details about this small APU (presumably Phoenix 2) were confirmed, and it's not just a simple hybrid version of the larger 8-core Phoenix design used in the higher-end models.

The original rumor suggested that Phoenix 2 would feature in the Ryzen 3 7440U and Ryzen 5 7540U, and since the 7540U is advertised as not having Ryzen AI and 4 GPU cores, this is plausible. However, I asked AMD to confirm whether the Ryzen 5 7540U used this new APU, and I was told it's "just the 7440U for now".

via XDA-Developers

Now technically, having Zen 4 and Zen 4C cores shouldn't make for a huge difference because, unlike Intel's P-Core and E-Core implementation, the Zen 4 variants feature the same ISA & the differences mainly lay within the L3 cache per core which is reduced to 2 MB from 4 MB on the standard Zen 4 cores. This means that the AMD Ryzen 5 7440U "Phoenix 2" APU will feature 16 MB of L3 cache.

The current 6-core Ryzen 7040 APUs also come with 16 MB of L3 cache so once again, there is no major difference. A big difference however will be the package size since Zen 4C cores are more compact and have a much smaller die size of 137mm2 versus the standard Phoenix chips that measure 178mm2.

Phoenix2 top die is 7540U (2 high+4 low), but 7540U is dual sourced: some chips will be full Phoenix2 dies (2+4), some will be cut down Phoenix1 dies (since Zen4c is just a downclocked Zen4, it's easy to bin it down from 8 high-clock cores to 2 high-clock + 4 low-clock cores)

— Бусыгин Алексей (@BusAlexey) June 29, 2023

AMD recently stated that it won't be following Intel's hybrid P-Core & E-Core architectural approach and rather use a mix of IPs of the same ISA that are workload-optimized. There were also reports of a Ryzen 5 7540U APU with a 2+4 (Zen 4 + Zen 4C) configuration but that hasn't been confirmed by AMD yet. It is expected that the AMD Phoenix 2 APUs will launch somewhere between Q4 2023. The APUs will probably be used in power-efficient PC gaming handhelds or laptops.