DEV Community

Izanagi
Izanagi

Posted on

CPU core parking: the hidden FPS killer on Windows

CPU core parking is a power management feature in Windows that shuts down CPU cores that aren't being used. The idea is to save power when load is low.

The problem: games have bursty load patterns. When a game suddenly needs a parked core, there's a wake-up latency before that core is available.

What you see in-game

Core parking causes frame time spikes — not consistently low FPS, but moments of stutter. A 1% low that's much lower than your average FPS is a common symptom. The average looks fine, but the worst frames are bad.

Checking if cores are parked

In Task Manager (Performance tab), if you see some CPU cores at 0% constantly even during gaming, they're parked.

More accurate: open Performance Monitor, add "% of Maximum Frequency" counter, check if any cores are below 100% during a game.

The fix

# Disable core parking (set min processors to 100%)
powercfg /setacvalueindex scheme_current sub_processor 0cc5b647-c1df-4637-891a-dec35c318583 100
powercfg /setactive scheme_current

# Lock min/max CPU frequency to 100%
powercfg /setacvalueindex scheme_current sub_processor 893dee8e-2bef-41e0-89c6-b55d0929964c 100
powercfg /setacvalueindex scheme_current sub_processor bc5038f7-23e0-4960-96da-33abaf5935ec 100
powercfg /setactive scheme_current
Enter fullscreen mode Exit fullscreen mode

Hybrid CPU note (Intel 12th/13th/14th gen, AMD X3D)

On hybrid CPUs with P-cores and E-cores, you also want to ensure game threads are pinned to P-cores:

HKLM\SYSTEM\CurrentControlSet\Control\PriorityControl
HeterogeneousSchedulingPolicy = 4
Enter fullscreen mode Exit fullscreen mode

This tells the scheduler to prefer efficiency cores for background tasks and performance cores for foreground threads.

All of this is in IzanagiOP's Spread Pack — it handles core parking, boost mode, P-core preference, and power frequency locking. Discord: https://terweb.lt/

Top comments (0)