Leaked Zen 6c EPYC CPU shows 24% single-threaded IPC gain over Zen 5 in benchmarks

Zen 6c EPYC 9996 Benchmarked

A leaked GeekBench 7 result for AMD's EPYC 9996 server CPU, featuring Zen 6c architecture, has emerged. This server processor, part of the EPYC 9006 family, is not yet widely available for third-party testing. The benchmark was spotted by HXL and further analyzed by "three twenty six" (@326powah).

Performance Comparison with Zen 5

The EPYC 9996 was directly compared to a Zen 5-based Ryzen 7 9700X desktop CPU. Both processors were clocked at 4.1 GHz for the single-threaded GeekBench 7 tests. The Zen 6c EPYC 9996 scored 2847 in the single-threaded test, while the Zen 5 Ryzen 7 9700X scored 2483 in Linux and 2318 in Windows.

This comparison revealed a performance difference of up to 24% in favor of the Zen 6c core in the HTML5 benchmark when comparing Linux results.

Architectural Details of EPYC 9996

The AMD EPYC 9996 is a large server processor with 256 Zen 6c cores, distributed across eight "Monarch" CCDs, each containing 32 cores. Each CCD includes 128MB of L3 cache, split into two 64MB domains for every 16-core CCX, maintaining a 4MB L3 cache per CPU core ratio. The full EPYC 9996 features a total of 1GB of L3 cache.

The processor also utilizes a 1024-bit memory bus, likely operating at 12,800 MT/s, providing 1.64 TB/second of memory bandwidth. However, memory bandwidth was not a bottleneck for the single-threaded Geekbench 7 workloads.

Implications for Future AMD Processors

The significant single-threaded IPC gain observed in these early benchmarks suggests substantial architectural improvements in the Zen 6c core. While these are preliminary results from a server-grade CPU, they offer an early indication of the performance capabilities expected from AMD's next-generation Zen 6 architecture.