This was lost in the switch to the new build system. -O3 provides around a 10% performance gain compared to -O2, see e.g. nix-env.qaAggressive.time in https://hydra.nixos.org/job/nix/master/metrics.nixpkgs#tabs-charts.
This was lost in the switch to the new build system. -O3 provides around a 10% performance gain compared to -O2, see e.g. nix-env.qaAggressive.time in https://hydra.nixos.org/job/nix/master/metrics.nixpkgs#tabs-charts.