Windows does not natively support permanently saving processor affinity for applications, but you can achieve persistent affinity using scripts or third-party tools. 1. Processor affinity binds a process to specific CPU cores, improving performance or thermal management, though Windows resets it on each launch. 2. Use a batch script with start and wmic commands to launch the app and set affinity via CPU mask values (e.g., 1 for CPU 0, 3 for CPUs 0 1). 3. Automate the script using Task Scheduler to run at startup or logon, ensuring consistent application of affinity. 4. For true permanence, use Process Lasso, which allows creating persistent rules that automatically apply affinity when the process starts. 5. Windows avoids permanent affinity by default to enable dynamic scheduling for optimal performance, so manual methods are required only when specific control is needed. The best approach is using Process Lasso for automatic, persistent affinity across reboots and restarts.

Changing the processor affinity for an application permanently in Windows isn't directly supported through standard settings—Windows doesn’t save affinity preferences by default when a process closes. However, you can achieve a permanent effect by using automation or third-party tools. Here’s how to do it effectively.

1. Understanding Processor Affinity

Processor affinity means binding a process to specific CPU cores. This can help with performance tuning, reducing context switches, or managing thermal load. But by default, Windows resets affinity each time the application starts.

2. Use a Batch Script with start and wmic (Built-in Tools)

You can create a script that launches your app and sets its affinity at startup. This is the most reliable built-in method.

Steps:

1. Open Notepad.
2. Paste the following script, replacing the app path and CPU mask:

@echo off
start "MyApp" "C:\Path\To\Your\App.exe"
timeout /t 3 >nul
wmic process where "name='App.exe'" call setaffinity "1"  # '1' = CPU 0, '3' = CPU 0 1, '4' = CPU 2, etc.

• CPU Mask Example:
  • CPU 0 → 1
  • CPU 1 → 2
  • CPU 0 & 1 → 3
  • CPU 2 → 4
  • All 4 cores → 15 (1 2 4 8)

3. Save as LaunchApp.bat.
4. Use this batch file to start the app every time.

? Pro tip: Place the shortcut to this .bat file in Startup folder if you want it to run on login.

3. Use Task Scheduler for Automatic Affinity on Launch

You can combine a script with Task Scheduler to simulate permanent affinity.

Setup:

• Create the batch script above.
• Open Task Scheduler → Create Task.
• Set:
  • Trigger: At logon or "On startup".
  • Action: Run the batch script.
  • Check "Run with highest privileges" if needed.
• Use a shortcut to trigger the task if needed.

This won’t set affinity every time the app is opened unless you always launch via the task or script.

4. Third-Party Tools for True "Permanent" Affinity

These tools monitor and enforce affinity automatically:

Recommended Tools:

• Process Lasso (Free & Pro versions)

  • Lets you set CPU affinity rules per process.
  • Rules persist across reboots and app restarts.
  • Example: Add a rule for chrome.exe → Affinity = Cores 0 and 1.

• CPU Power Governor or Thread Master (less common, use with caution)

Process Lasso is the most trusted option. It runs in the background and applies rules the moment the app starts.

5. Why Windows Doesn’t Allow Permanent Affinity by Default

The OS scheduler is designed to optimize core usage dynamically. Manually locking apps to cores can reduce performance unless you have a specific reason (e.g., reducing latency in real-time apps, avoiding core parking issues, or thermal management on laptops).

Summary: Best Way to Make It Permanent

• ? Not possible via standard Windows settings.
• ? Use a batch script wmic for simple cases.
• ? Use Process Lasso for true persistent, automatic affinity.

Basically, you need a tool or script that re-applies the setting each time the app launches—Windows won’t remember it on its own.

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