Based on informal benchmarking of running various implementations over large chunks of CSS containing only very simple style rules and declarations, I got the following best run numbers:
- sassc: 1.439s
- Dart Sass: 2.301s
- Ruby Sass with a hot cache: 15.023s
- Ruby Sass without caching: 18.488s
Based on these numbers, Dart Sass is approximately:
- 1.6x slower than libsass
- 6.5x faster than Ruby Sass with a hot cache
- 8x faster than Ruby Sass when it has to parse as well