MacFix
Does Rosetta 2 slow down apps on Apple Silicon?
After this, you'll know whether a specific app is actually running translated, instead of guessing from how it feels.
On this page
Yes, Rosetta 2 has a real performance cost — early independent testing put translated code at roughly 78–80% of native speed — but for most everyday apps that difference isn't something you'd actually feel; it shows up mainly on CPU-heavy work like video encoding or machine learning. Before blaming Rosetta for a slow app, confirm it's actually running translated at all, since plenty of apps that used to need it are native now.
Why this happens
Rosetta 2 translates Intel (x86_64) code to Apple Silicon (arm64) instructions, either ahead of time on first launch or on the fly. Apple caches the translated result on disk so subsequent launches skip re-translation — which is also why the very first launch of a translated app right after installing or updating it can take noticeably longer than every launch after. That first-launch delay is often what people actually notice and misattribute to "Rosetta being slow" generally, when it's really a one-time cost per app version.
Rosetta isn't going away immediately, but it is on a clock worth knowing about: Apple has said Rosetta 2 remains fully available through macOS 27, and starting with macOS 28 only a limited subset — scoped specifically to older, unmaintained game titles — will still be supported. Everyday business software, plugins, and utilities that still depend on Rosetta past that point will simply stop running. If you depend on a specific translated app for work, it's worth checking now whether a native build exists rather than waiting.
Fix it
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Check whether a running app is actually translated before assuming it is: open Activity Monitor, add or check the Kind column (View menu → Columns, if it's not already showing) — it reads Apple for native arm64 processes and Intel for anything running under Rosetta. This is the most reliable way to check a process that's already running.
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To check an app you haven't launched yet — useful before installing something you suspect might be Intel-only — inspect the binary itself:
Reads the system
What it does: prints which CPU architectures the app's binary was built for.
After: nothing changes, this only reads.
file "/Applications/Example.app/Contents/MacOS/Example"A universal binary (native on both architectures) reports something like Mach-O universal binary with 2 architectures: [x86_64] [arm64] — it'll run natively on your Mac. An app that reports only x86_64 has no native arm64 build and will always run under Rosetta, no matter how it's launched.
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If the app genuinely is Intel-only and the slowdown is real, the actual fix is outside Rosetta itself: check the developer's site for a newer, universal build, or look for a native alternative. Rosetta's own translation overhead isn't something you configure or tune away — it's fixed per app, not per system.
Still broken?
Verified on
| Chip | macOS | Verified |
|---|---|---|
| M1 (MacBook Air) | 26.6 | 2026-09-08 |
| M2 Pro (Mac mini) | 26.6 | 2026-09-08 |
| M3 (MacBook Pro) | 26.6.2 | 2026-09-08 |
| M4 (MacBook Pro) | 26.6 | 2026-09-08 |