PHP 7.4–8.6 Benchmarks: JIT Gains and a Regression in 8.6 Git

Benchmark Request and Scope

A Phoronix Premium member requested updated performance benchmarks for the latest PHP versions. The author tested every major release from PHP 7.4 up to PHP 8.5, plus the current PHP 8.6 Git development branch (PHP 8.6.0 is slated for stable release later in 2026). PHP 8.6 is the first version to ship with the JIT compiler enabled by default, allowing deeper insight into its impact.

Test Environment

Hardware: Intel Xeon 678X (HP Z4 G6i workstation)

OS: Fedora 44

Compiler toolchain: GCC 16 (earlier PHP versions segfault with this toolchain, so PHP 7.4 is the oldest tested)

Build method: All versions compiled from their respective Git branches using the identical toolchain on Fedora 44

Execution mode: Command-line driven benchmarks to eliminate web-server overhead

PHPbench Results

The widely used PHPbench suite shows that performance improvements across the PHP 8.x series have been gradual. Notably, the PHP 8.6 Git build regresses relative to PHP 8.5. The author expresses hope that this regression will be fixed before the stable PHP 8.6 release expected in late 2026. Including older PHP 5 and PHP 7 branches would have produced more dramatic contrasts, but modern toolchain incompatibilities prevent their inclusion.

Built-in Microbenchmarks

PHP's integrated microbenchmarks do not show striking differences between versions. In the author's own test runs, PHP 8.5 and later perform well and do not exhibit the PHPbench regression seen in the 8.6 Git snapshot.

JIT Impact

With JIT enabled, PHP 8.6 delivers a modest performance uplift in microbenchmarks. The author notes that comparisons with PHP 5 and PHP 7 would be even more compelling and may be revisited in a follow-up article.

Conclusion

Aside from the PHPbench regression in the 8.6 Git build, PHP 8.6's performance looks solid, offering incremental gains over PHP 8.5. The author plans to re-evaluate PHP 8.6 performance ahead of its official stable release.