Cloud provider Cloudflare has upgraded its server infrastructure with AMD’s latest generation EPYC Genoa-X processors armed with 3D V-Cache technology. Cloudflare reports a 145% improvement in performance and a 63% improvement in efficiency over its previous generation servers, which were also EPYC-powered.
The new "Gen 12" servers come with AMD’s EPYC 96-Core 9684X Genoa-X processor featuring over one gigabyte of L3 cache. The system features 384GB of DDR5 4800MHz DDR5 memory operating in a 12-channel memory configuration, dual E1.S NVMe Samsung PM9A3 7.68TB or Micron 7450 Pro 7.68 TB SSDs, dual 25GbE Intel or Nvidia Mellanox networking, and a 800W titanium grade PSU.
Before focusing on the 9684X, Cloudflare conducted an extensive survey of the CPU landscape to determine which model would best suit its needs. The cloud service provider purportedly evaluated “many candidates in the lab” but ultimately shortlisted three AMD CPUs for evaluation, knocking out any Intel Xeon CPUs.
The three in question were the EPYC 9654, EPYC 9754, and the EPYC 9684X, which the provider eventually selected. The EPYC 9654 is the vanilla (non-X3D) variant of the 9684X, sporting 96 cores, 192 threads, 384MB of L3 cache, and a max turbo clock of 3.7GHz. The EPYC 9754 is a Burgamo Zen 4c powered CPU featuring 128 cores, 256 threads, 256MB of L3 cache, and a max boost clock of 3.1GHz. The 9684X features the same specs as the 9654 but with 1,152GB of total L3 cache.
These chips were evaluated against Cloudflare’s previous 11th-gen servers powered by the 64-core AMD EPYC 7713. The 9654, 9754, and 9684X were tuned to their max 400W configurable TDPs; the EPYC 7713 maximum TDP is 240W. All the chips were effectively benchmarked under a real-world workload, with each server set up to run the same processes and services as its production servers.
Cloudflare discovered that all three chips were at least 2x faster than the previous EPYC 7713 CPUs. The Genoa 9654 was exactly 2x faster than the 7713, the Bergamo 9754 was 2.15x quicker, and the Genoa-X 9684X was 2.45x faster. In terms of efficiency, Cloudflare discovered that the Genoa 9654 was 33% more power efficient than the EPYC 7713, the Bergamo 9754 was 38% more efficient, and the 9684X was the most efficient of the bunch, being 63% more power efficient.
Cloudflare provided specific details on the performance enhancements offered by AMD's 3D V-Cache technology, noting a massive 22.5% performance delta between the 9654 and 9684X in the tests it ran. The service provider said its workload benefits from more accessible low-level caches, avoiding trips to DDR5 memory, which introduces significant system latency.
The 9684X also delivered this 22.5% performance improvement within the same power envelope as the 9654. The 9684X's 3D-stacked L3 cache purportedly consumes additional power, but the difference only affected maximum all-core turbo clock speeds by just 3%.
With these results, it's obvious why Cloudflare opted for the 96-core EPYC 9684X for its 12th-gen servers. Its particular applications take full advantage of the extra cache offered on AMD's 3D V-Cache-equipped Genoa-X CPUs, boosting performance more than even the EPYC 9754 with its 128 cores.
