Like a compact car with great mileage, AMD’s Zen 4C core delivers a big improvement in power and area efficiency over Zen 4. The efficiency gains enabled the company to create Bergamo, which extends its server lineup to 128 cores. At its base frequency, the 128-core Epyc 9754 offers 25% more raw performance than AMD’s 96-core Epyc 9654 (Genoa), the top-of-the-line introduced late last year, without raising power. Bergamo is already in production and available to customers. Zen 4C implements the same Zen 4 microarchitecture in the same 5 nm process, but the designers chose smaller, low-power gates to optimize for a lower operating frequency. This approach reduced the CPU’s area by 34%, enabling AMD to pack 16 cores per die, twice as many as in Genoa. But whereas Zen 4 can reach 5.7 GHz in PC processors, Zen 4C tops out at 3.1 GHz in the Bergamo products. The latter speed is a bit low even for server processors, which sometimes reach 4.0 GHz or faster; thus, AMD positions Bergamo for microservices and other light workloads that don’t require high per-thread performance. Bergamo (pronounced BER-gah-mo, like the Italian city) extends AMD’s performance lead over Intel’s recent Sapphire Rapids products, which top out at 60 cores. By improving power efficiency, it also adds to AMD’s advantage in that metric. Bergamo raises the bar for Sierra Forest, Intel’s power-efficient server processor scheduled to reach production a year from now. In the meantime, the new processor puts pressure on power-efficient Arm processors that have been encroaching into the data center. Taking Genoa in a different direction, AMD also introduced Genoa-X, which applies the company’s 3D V-Cache technology to triple cache size. The new Epyc 9684X sports an incredible 1.1 GB of cache memory, making it ideal for HPC and similar applications. Following last year’s Milan-X, Genoa-X is AMD’s second server product with V-Cache, which employs 3D stacking to apply a memory chip atop each compute die.