Slack, Chrome, Docker, Node : Sourdine hands them off to your Mac's efficiency cores — or freezes them completely when you're not looking at them. Less fan noise, more battery. And only honest numbers.
installs (opt-in)
Install for free, activate with a license. macOS 13+, Apple Silicon · see the measurements
Fleet aggregates — opt-in, anonymous telemetry, no identifiers. Methodology below.
Built for developers and creatives on macOS — and described without exaggeration.
The only guaranteed gain : a frozen process consumes exactly 0% CPU, deterministically and verifiably with ps. Instant wake-up as soon as it's back in the foreground.
Your background apps move to macOS's background scheduling policy (taskpolicy) : Apple's scheduler then favors the efficiency cores. Sourdine verifies the policy actually took effect, and counts CPU time under verified policy — not placement promises.
Less contention on the performance cores during your builds : background tasks step aside, your IDE and your builds keep the priority.
A native Swift utility, zero dependencies, an adjustable wake interval (1 to 10 s). The overhead is designed to stay negligible — and you can see it for yourself in Activity Monitor.
Every number Sourdine shows belongs to one of these three categories, and says so.
A process under SIGSTOP is in state T : 0% CPU, no exceptions. It's the product's strongest claim, and anyone can verify it with ps.
After each taskpolicy application, Sourdine re-reads the process's priority band and only counts CPU time "under eco policy" once the policy is confirmed. Final thread placement is still decided by Apple's scheduler — we never claim otherwise.
Energy saved is derived from CPU time via a model specific to each chip family, shown as a low–high range and always labeled "estimate." Never presented as a wattmeter measurement.
Reproduce our checks on your own machine : the benchmark.sh script shipped with the app exercises all four policies and shows the real process states. The fleet aggregates on this page come from opt-in, anonymous telemetry with no identifiers — the IP address is never recorded.
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The app installs for free — this license activates the optimization engine.
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