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What Win32PrioritySeparation actually does to your game performance

Win32PrioritySeparation is a registry value that controls how Windows distributes CPU time between foreground and background processes. It's one of those settings that sounds obscure but has a direct effect on game smoothness.

How Windows scheduling works

Windows uses a priority-based scheduler. Each thread has a base priority (1-31). But there's also a boost system where foreground applications get a temporary priority bump.

Win32PrioritySeparation controls:

  1. How large the foreground boost is
  2. How long each scheduling quantum lasts
  3. Whether foreground and background processes get equal or unequal time slices

The values

0x24 = 36 decimal: short intervals, equal foreground/background
0x26 = 38 decimal: short intervals, foreground gets 3x the time
0x28 = 40 decimal: long intervals, equal
0x2A = 42 decimal: long intervals, foreground gets 3x the time
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Default on Windows 11: 0x02 (adjusted by the UI setting "Adjust for best performance of Programs").

For gaming: 0x26 (38) — short quantum, foreground priority. Your game thread gets scheduled more often and holds the CPU longer per scheduling cycle.

HKLM\SYSTEM\CurrentControlSet\Control\PriorityControl
Win32PrioritySeparation = 38
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What you feel

The difference shows up in 1% lows and frame time consistency, not average FPS. Your average might stay the same but the worst frames get less bad. Games feel smoother because the scheduler is less likely to interrupt the game thread to run a background process.

This value is set by IzanagiOP across several packs (HitSync, Frame, StickSync). It's one of the base tweaks. Discord: https://terweb.lt/

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