AMD has published a new patch for the GNU Compiler Collection (GCC) surrounding Zen 5 and Zen 4 CPUs' branch predictors, helping boost the performance of Zen 5 CPUs by 12% and 9% for Zen 4. Reported by Phoronix, the new patch features just two lines, bumping the branch misprediction scale by three in the cost tables for both architectures.
The aforementioned performance results were taken from benchmarks using SPEC, or Standard Performance Evaluation Corporation's CPU benchmark. Not every app will gain an exact 9% or 12% performance improvement, but the SPEC benchmark shows what the average performance uplift could be on average across a variety of workloads.
The GNU Compiler Collection (GCC) is a collection of compilers that support various programming languages, hardware, and operating systems. In the case of CPUs, AMD uses GCC to program its CPUs on how they should run instructions on the chip, including the way the chip operates its branch predictor.
Phoronix reports that the new patch is expected to debut next year as part of GCC 17, however, the outlet also suggested the patch could be "back-ported" to the GCC 16.3 release. If true, we could see the patch drop this year rather than next year.
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The results of this patch mimic similar behavior that we saw back in 2024, when AMD published branch prediction improvements for Zen 3, Zen 4, and Zen 5 for Windows 11 23H2. The improvements in that update provided roughly a 10% performance improvement for gaming and productivity workloads.
