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> Phoenix 2 that will feature few good cores (Zen 5) and many crappy cores (Zen 5c). Phoenix 2 is already starting to ship, with Zen 4 and Zen 4c cores in a 2+
by wtallis 3y ago
> Phoenix 2 that will feature few good cores (Zen 5) and many crappy cores (Zen 5c).
Phoenix 2 is already starting to ship, with Zen 4 and Zen 4c cores in a 2+4 arrangement. I don't think there's anything wrong with this approach: the main downside of Zen 4c cores is they cannot clock as high, but the kind of systems the SoC is going into are thermally limited to the point that using more than two CPU cores is already guaranteed to drop you down to the clock speed range that Zen 4c runs at. Ignoring the impact on chip floorplan and just looking at the implications for software, it's more like a more pronounced version of Intel's Turbo Boost Max 3.0 (preferred cores) rather than the heterogeneous P vs E core situation. All the cores have the same feature support and same performance per clock and the same sizes for their private caches.
- treprinum 3y agoThe smaller cache will make it a heterogeneous situation for some workloads and likely games as well (seeing how 5800x3D/7800x3D are demolishing the competition thanks to a larger cache).
- wtallis 3y agoThere is no smaller cache. L1 and L2 are the same capacity (but smaller area) for Zen 4 and Zen 4c: 32kB and 1MB respectively. The L3 cache is 16MB for Phoenix and Phoenix 2, so it's actually more L3 per core for the 2+4-core Phoenix 2 than the 8-core Phoenix. It's only in the server Zen 4c processors (Bergamo) that they've cut L3 per CCX in half. Performance per clock has already been verified as the same: https://pic2.zhimg.com/v2-866cc994355fb54831c7398c97b20479_b.jpg https://pic2.zhimg.com/v2-866cc994355fb54831c7398c97b20479_b... The only heterogeneity experienced by software will be due to the lower maximum clocks on the Zen 4c cores, which is a far simpler problem to deal with than Intel's P vs E cores or AMD's 7950X3D with 3D V-Cache on only one of the two CPU chiplets.