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CPU Affinity Manager
Pin a program to specific processor cores, set its priority, and make the setting stick across restarts.
What is CPU affinity?
Your CPU has multiple cores — usually between 4 and 16 on a modern PC. By default, Windows is free to schedule any program onto any core. That's almost always the right behavior. But sometimes a specific program misbehaves on certain cores (older games that don't know what to do with 16 threads), or you want to keep a resource-hungry background task from hogging all the cores your foreground app needs.
CPU Affinity Manager lets you tell Windows "only run this program on these specific cores." It also lets you set the process priority — how important Windows considers this task when competing programs are demanding CPU time.
Features
- Live process list with CPU and memory usage, refreshing automatically.
- Per-core checkboxes reflecting your actual CPU topology.
- Priority selector: Low, Below Normal, Normal, Above Normal, High, Realtime.
- Saved profiles that remember your settings by program name.
- Auto-apply: TuneBit can watch for matching programs to launch and apply your saved profile immediately.
How to use it
- Go to Optimize → CPU Affinity.
- Find the program you want to tune in the process list. You can sort by name, CPU, or memory.
- Click it. The right panel shows its core checkboxes and priority.
- Check the cores you want it to run on. Uncheck the ones you want to block.
- Pick a priority. Normal is almost always correct — only change it for a specific reason.
- Tick Save Profile if you want this configuration remembered for next time.
- Click Apply.
Saved profiles and auto-apply
Saved profiles live in the bottom panel. Each one is associated with a program name (such as chrome.exe) — when that program starts, TuneBit's watcher applies the saved affinity and priority automatically. Enable this with the Auto-apply saved profiles checkbox. It's ideal when a specific app misbehaves every time.
Example use cases:
- Set a backup or antivirus scan to Low priority so it doesn't interrupt your work.
- Keep a single-threaded game on the first four cores to avoid scheduling-related stuttering.
- Pin a video encoder to your high-performance cores on an Intel P-core/E-core CPU.
Avoid "Realtime" priority. Realtime means "more important than Windows itself." A stuck Realtime process can freeze your entire PC. If you want a faster game or encoding run, stop at High. Also, don't uncheck every core — at least one must stay checked for a program to run at all.