Buzz
In short, Zen 4c is the power-saving version of Zen 4. It's designed with the philosophy of consuming less power, occupying less silicon area, thus producing more power-efficient chips while being economically advantageous in terms of production costs. Zen 4c was initially misunderstood as equivalent to Intel's 'E-core' or Efficient core.
In reality, AMD's Zen 4c and Intel's E-core follow very different paths. While Intel designs E-core based on the idea of using a different architecture from P-core (often an older, power-saving architecture for background tasks), Zen 4c is merely a 'slimmed-down' version of Zen 4. This means Intel's E-core architecture will lack many features compared to P-core, usually related to ISA instructions. On the other hand, Zen 4c (compact) still shares the same architecture as Zen 4, with no changes to the ISA.
So, how does Zen 4c differ from Zen 4? According to AMD's description, the fundamental difference lies in the size of the processing core. Despite using the same 5nm process from TSMC, Zen 4c's core size is only 2.48 mm2, 35% smaller than Zen 4's 3.84 mm2. This is achieved because AMD utilizes higher-density libraries on Zen 4c - the higher the IC density, the smaller the die chip area. However, the downside of this approach is that the chip cannot achieve high clock speeds like the full design (which requires more silicon). Therefore, AMD needs to maintain both Zen 4 & 4c designs simultaneously as each processing core will cater to different needs.
How many Zen 4c products will there be?
Despite its energy-efficient nature, Zen 4c might not cater well to applications demanding higher clock speeds. Consequently, there will be fewer Zen 4c models available. On the desktop platform, if any, these products will feature significantly lower TDP and clock speeds. For high-end models, AMD continues to rely on Zen 4 as its primary architecture.
