AMD announced Zen 4c-based EPYC 8004 series processors and new socket

AMD EPYC Genoa, Genoa-X, Bergamo and Sienna have one thing in common: They are powered by the AMD Zen 4 architecture and strategically address the high-core count market segment in the data centers, cloud computing and edge computing industry. The last of these series, the EPYC 8004 processor series codenamed Sienna, was officially announced today. AMD also introduced the SP6 socket platform on this occasion.

AMD EPYC 8004 series

These processors, whose processor core count can go up to 64 cores/128 threads, are based on the “Zen 4c” microarchitecture, which has the same IPC and ISA as “Zen 4” but comes with a smaller L3 cache per core. Although the majority of IT operations are carried out by remote data centers or cloud providers, smaller organizations are targeting more compact data centers on-site. EPYC 8004 series also focuses on this area.

With the EPYC 8004 series, AMD is introducing a new, smaller CPU socket called SP6. The socket has dimensions of 58.5 mm x 75.4 mm, compared to 76.0 mm x 80.0 mm of the Socket SP5 that powers the EPYC 9004 “Genoa” and EPYC 97×4 “Bergamo”. The EYPC 8004 series, codenamed Siena, will also use this new SP6 socket. Siena processors are part of the 4th Generation EPYC series, which consists of “Genoa” for data center servers, “Genoa-X” for compute servers and “Bergamo” for high-density cloud.

Detail

EPYC 8004 family is a chiplet-based processor series, just like the Genoa family. It uses the same 6nm server I/O die (sIOD), but its I/O capabilities have been cut nearly in half. This sIOD is surrounded by four 5nm CCDs (core chip dies), codenamed “Vindhya”. Each of these also has 16 CPU cores based on the “Zen 4c” microarchitecture, distributed across two CCXs (CPU core complex). Each CPU core complex incorporates eight “Zen 4c” cores sharing 16 MB of L3 cache. Each of these cores comes with 1 MB L2 cache.

In simpler terms, the new “Zen 4c” CPU core can be thought of as a zipped version of the “Zen 4” core. Therefore, there are no missing hardware features. Since both types of CPU cores have the same IPC and the same instruction sets, any software designed specifically for EPYC “Genoa” will run smoothly on “Siena”. Since the “Zen 4c” core has a 35 percent smaller footprint compared to the “Zen 4”, AMD has managed to produce a die (CCD) with 16 of these cores, albeit with smaller L3 caches.

AMD EPYC 8004 processors come with leaner I/O than their Socket SP5 cousins. The processor only has a 6-channel DDR5 memory interface, and this interface can support up to 1,152 GB of ECC DDR5-4800 RDIMM memory. The PCI-Express root complex has also been overhauled. “Siena” offers a total of 96 PCI-Express Gen 5 lanes and 48 CXL 1.1 lanes.

EPYC 8004 “Siena” generally has a lower TDP compared to “Zen 4”-based EPYC 9004 “Genoa” processors with similar core counts ranging from 200W to 400W. This is due to sIOD operating at generally lower frequencies, more CPU cores per CCD, fewer CCDs, smaller caches, and reduced I/O capabilities.

Performance

In terms of performance, AMD says the single-socket system offers up to twice the performance per Watt compared to the 4th Gen Intel

The company also claims that at the same core counts, the 32-core/64-thread EPYC 8324P achieves approximately 16 percent higher video transcoding performance (FFmpeg) per core compared to the Xeon 6421N. The company also has a large ecosystem of companies that design server motherboards, full-fledged server blades, and racks around these processors.

Summary and EPYC 8004 features

Unlike primary EPYC Zen4 CPUs like the “Genoa” that prioritize performance, cache size, and memory-intensive applications, Sienna processors focus on performance per watt and price advantage. AMD positions these processors as ideal solutions for energy-efficient cloud services, intelligent edge computing and telecom deployments. The AMD EPYC 8004 series covers a range of Zen4 cores, including 8, 16, 24, 32, 48 and 64 cores, while featuring various Thermal Design Power (TDP) levels ranging from 80W to 200W (default TDP). Some models can also be configured to reach up to 225W. These CPUs also support up to 6-channel DDR5-4800 memory, offering up to 1,152 TB capacity. Additionally, up to 96 PCIe Gen5 lanes and 48 CXL 1.1+ lanes are also offered.

EPYC 8004 SKU, known as the flagship of the series, has 8534P, 64 cores, 3.1 GHz boost and 220W TDP. AMD is also launching an 8-core EPYC 8024 that will clock up to 3.0GHz and run with a default TDP of 90W. You can see all processors and prices in the image below.