JetStream 3 Debuts as a Major Browser Benchmark Update

JetStream 3 has been introduced as a major upgrade to one of the most widely recognized browser benchmarking tools, representing its first substantial update since 2019.

For those unfamiliar, JetStream is a benchmark suite used to evaluate browser performance in handling JavaScript and WebAssembly workloads. It specifically targets compute-heavy operations found in modern web applications, rather than focusing on page rendering or user interface responsiveness.

The new version was announced by the BrowserBench project, with contributions from developers at companies such as Apple, Google, and Mozilla. According to Chromium’s blog, JetStream 3 was created through an open, consensus-based development process involving engineers from all major JavaScript and WebAssembly engine teams.

A key change in JetStream 3 is its focus on larger and more modern workloads. The BrowserBench team has reduced or removed older microbenchmarks, placing greater emphasis on scenarios that better reflect real-world web usage today.

WebAssembly plays a much larger role in this release, with 12 dedicated workloads included. It also supports newer features such as exception handling, SIMD, and WasmGC. Additionally, the benchmark has expanded beyond its traditional reliance on C and C++, now incorporating workloads developed in languages like C#, Dart, Java, Kotlin, Rust, and C++.

On the JavaScript side, JetStream 3 adds or updates tests covering startup performance, asynchronous operations, React server-side rendering, TypeScript compilation, 3D engines, tokenization, proxies, and class fields. Several older asm.js-based tests have been removed.

In conclusion, while benchmarks like Speedometer are designed to measure everyday browser responsiveness, JetStream continues to serve as a strong indicator of how well browser engines handle demanding, computation-heavy workloads. This latest version represents a significant advancement in that area.