LLVM Clang 21 Compiler Helping Squeeze More Performance On 5th Gen AMD EPYC "Turin"

Written by Michael Larabel in Software on 2 September 2025 at 10:42 AM EDT. Page 5 of 5. 5 Comments.

👁 C-Ray benchmark with settings of Resolution: 4K, Rays Per Pixel: 16. Clang 21.1 was the fastest.

👁 C-Ray benchmark with settings of Resolution: 5K, Rays Per Pixel: 16. Clang 21.1 was the fastest.

There were some performance improvements with compiling C-Ray under Clang 21.

👁 oneDNN benchmark with settings of Harness: IP Shapes 1D, Engine: CPU. Clang 20.1 was the fastest.

👁 oneDNN benchmark with settings of Harness: Recurrent Neural Network Training, Engine: CPU. Clang 21.1 was the fastest.

👁 oneDNN benchmark with settings of Harness: Recurrent Neural Network Inference, Engine: CPU. Clang 21.1 was the fastest.

👁 OpenSSL benchmark with settings of Algorithm: SHA256. Clang 21.1 was the fastest.

👁 OpenSSL benchmark with settings of Algorithm: AES-256-GCM. Clang 20.1 was the fastest.

In many other workloads, there wasn't much to report with Clang 21 over the Clang 20 performance.

👁 Liquid-DSP benchmark with settings of Threads: 128, Buffer Length: 256, Filter Length: 32. Clang 21.1 was the fastest.

👁 Liquid-DSP benchmark with settings of Threads: 256, Buffer Length: 256, Filter Length: 32. Clang 21.1 was the fastest.

👁 Liquid-DSP benchmark with settings of Threads: 512, Buffer Length: 256, Filter Length: 57. Clang 21.1 was the fastest.

👁 Liquid-DSP benchmark with settings of Threads: 768, Buffer Length: 256, Filter Length: 57. Clang 21.1 was the fastest.

👁 Liquid-DSP benchmark with settings of Threads: 768, Buffer Length: 256, Filter Length: 512. Clang 21.1 was the fastest.

The Liquid-DSP digital signal processing library did see better performance with its Clang 21 build on this AMD EPYC 9965 2P server.

👁 Geometric Mean Of All Test Results benchmark with settings of Result Composite, LLVM Clang 21 On AMD EPYC Zen 5. Clang 21.1 was the fastest.

On the whole over five dozen benchmarks carried out of Clang 20 and Clang 21 from this AMD EPYC 9965 2P server running Debian 13 with Linux 6.16, Clang 21 yielded binaries around 5% faster than Clang 20 on a geo mean basis. More Clang 21 compiler benchmarks on other CPUs will be coming as well as scoping out how Clang 21 is competing against the latest GCC 15 open-source compiler too for that healthy competition on x86_64 and AArch64 Linux systems.

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⇱ LLVM Clang 21 Compiler Helping Squeeze More Performance On 5th Gen AMD EPYC "Turin" - Phoronix

LLVM Clang 21 Compiler Helping Squeeze More Performance On 5th Gen AMD EPYC "Turin"