AMD’s Hybrid Core processor (Big Little) in picture: Two Zen 4 cores and four Zen 4c cores

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AMD's hybrid core processor (big small) in photo: Two Zen 4 cores and four Zen 4c cores | Hardware Times

AMD's first hybrid core processor, also known as big.LITTLE in Arm terminology, was first spotted, thanks to 金猪升级包. Codenamed Phoenix 2, these APUs will be part of the Ryzen 7040 family, with a smaller surface area and improved power efficiency. In the photo below you can see the vanilla Phoenix on the left and the Phoenix 2 on the right. Thanks to the smaller Zen 4c cores, the latter is ~23% more compact than the former:

As noted several times, AMD's approach to heterogeneous architecture is much simpler than Intel's. Instead of using a completely different ISA (like Intel's Monts), AMD decided to reduce the size of its existing Zen 4 core. This provides the same benefit: a smaller footprint and improved power efficiency without the challenges of using a second ISA.

According to @BusAlexey (Twitter), the high-end Phoenix 2 processor is doubly stocked. This means that part of it will be fully activated Phoneix 2 matrices, while the rest will be derived from reduced Phoneix matrices. The Zen 4c cores on the Phoenix 2 chips are simply stripped-down Zen 4 cores running at lower clocks. It is unclear whether the L3 cache has been further reduced or whether the floor plan has been optimized based on available space.

Regardless, this arrangement allows AMD to downclock certain cores on the Pheonix chips and name them Phoenix 2. The Ryzen 5 7540U will be the highest-end Phoenix 2 chip. It will feature two Zen 4 cores capable of high frame rates and four Zen 4c cores running at lower frame rates for better power efficiency.

AMD Bergamo

It's worth noting that these likely aren't the same Zen 4c cores we've seen on the Epyc Bergamo chips. Each of these DCCs includes 16 cores, twice as many as normal Zen 4 DCCs. The DCC Phoenix 2 is probably just a repurposed 8-core DCC. In the future, we might see similar designs for mobile Ryzen components with a mix of 8- and 16-core DCC, but we can't confirm anything.

In addition to the 6 cores and 16 threads, the Phoenix 2-based Ryzen 7540U will consist of 4 RDNA 3 compute units. This is a fraction of what the high-end Phoenix chip offers (up to 12 CUs), but it is logical if we consider the reduction in the calculation surface.

AMD Ryzen Phoenix 2 mobile processors will be released closer to the holiday season. Limited volume is to be expected, some of which will be for custom OEM handhelds and laptops.


Computer hardware enthusiast, PC gamer and almost engineer. Former co-founder of Techquila (2017-2019), a successful technology site.
Worked on Hardware Times since 2019, an outlet dedicated to computer hardware and its applications.

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