Intel P-cores and E-cores in games: Thread Director and APO

You have an Intel Core i5, i7 or i9 from the 12th generation onward, or a Core Ultra 200S, and a game stutters or runs below what you expected. Somewhere you read that the game is landing on the "slow" cores, and that the fix is to switch the E-cores off in the BIOS, pin the game to the P-cores, or stay on Windows 10.

Each of those changes how Windows places a game's threads. Here is what does the placing, and what has been measured.

Two kinds of core

Intel's game developer guide for 12th gen Core names them: "Performance-cores or P-cores" and "Efficient-cores or E-cores", combined in one hybrid processor. How many of each you have depends on the model:

All figures come from Intel's specification pages, which also list Intel Hyper-Threading Technology as "No" for the three Core Ultra models. Not every model is hybrid: Intel lists the i5-12400 with 0 E-cores and Intel Thread Director as "No". Your model's specification page on Intel's site has the same fields.

Thread Director and Windows 11

Intel's guide describes Thread Director as giving the operating system awareness of "performance differences (and power-efficient changes) between the Performance-cores and Efficient-cores". The scheduler still decides; Thread Director advises. In Intel's words: "With the release of Windows 11, you can automatically have your threads scheduled by the OS using hardware hints from Intel Thread Director", and "Without the updates for Windows 11, Intel Thread Director will not be supported." The guide also shows developers how to mark background work so that it is preferably placed on the E-cores.

On Windows 10 the sources differ in emphasis. ComputerBase measured Alder Lake on both systems in November 2021 and found the same average result. It reported an Intel engineer from the Alder Lake project explaining that Windows 10 uses a slightly earlier version of the Windows 11 scheduler that is "keinesfalls ungeeignet", by no means unsuitable. It added that optimisations could reach Windows 11 first, and that even Windows 11 had edge cases where the scheduler stayed on the P-cores, or used the E-cores when the P-cores should have had the work.

Windows 10 support ended on October 14, 2025: Microsoft no longer provides software updates or technical support for it, and security updates only through the Extended Security Updates program.

Power settings take part

Windows' processor power settings are split by core type on these chips. Microsoft's documentation for PC makers says that on processors with a heterogeneous architecture, the settings for "efficiency class 1 cores" follow a similar naming convention, so values such as core parking and the energy performance preference can be set separately for the two classes of core. For that preference, which Microsoft documents for processors running in autonomous mode, 0 favours performance and 100 favours energy savings; it is listed as a hidden setting of the power policy.

When the Core Ultra 200S launched, Intel itself named the Balanced power profile as costing a lot of performance, along with APO not being active in supported games, as ComputerBase reported in December 2024. After microcode, Windows and game updates, ComputerBase measured that Balanced no longer cost what it had at launch. Keep BIOS, Windows and games current, and leave the values inside Windows' own plans at their defaults. If a tool or guide changed them, w0a's Processor power settings card returns the core-parking and minimum and maximum processor state values in Windows' own plans to the plan defaults.

APO: per-game scheduling from Intel

Intel Application Optimization, APO, is Intel's per-title layer on top of this. Intel's APO overview says it "optimizes thread scheduling along with application threading for selected software titles". As of that page's June 2026 review, the verified desktop processors are:

• Core Ultra 7 270K Plus, Core Ultra 5 250K Plus and 250KF Plus
• Core Ultra 9 285K, Core Ultra 7 265K and 265KF, Core Ultra 5 245K and 245KF
• Core i9-14900KS, 14900K and 14900KF, Core i7-14700K and 14700KF, Core i5-14600K and 14600KF

What it needs, per the same page: BIOS enablement and Intel Dynamic Tuning Technology (DTT), which comes from your motherboard or system manufacturer; the Intel Platform Performance Package; an optional user interface from Intel's download centre; and Windows 11, with 25H2 or later recommended. Intel's DTT page adds that APO depends on DTT and firmware support.

APO acts only on the titles Intel selected. Intel's Advanced Mode game list, last reviewed in June 2026, includes Counter-Strike 2, Cyberpunk 2077, Dota 2, Rainbow Six Siege and Valorant. Which titles appear varies by platform and configuration, and "availability of newly added games is also dependent on system manufacturer deployment". For 12th to 14th gen chips outside the verified list, Intel offers "Limited support with Advanced Mode", which shows additional titles that have not been validated, with Intel's own caveat that "results may vary, including potential performance degradation".

Old games that would not start

At Alder Lake's launch, Intel acknowledged a DRM issue with 12th gen processors that made some games crash or not load on Windows 11 and Windows 10. ComputerBase explained the Denuvo case: Denuvo treated P-cores and E-cores as different CPUs, so a change of the first core it registered between two game starts counted as a CPU change, and five changes within 24 hours locked the game for 24 hours. Intel's interim workaround was a BIOS switch, Legacy Game Compatibility Mode, used with the Scroll Lock key. Intel's page now says "all games originally identified as having this DRM issue have been fixed through game patches or OS updates" and advises running the latest version of Windows Update. For an old game that still will not start, update both Windows and the game first.

Switching E-cores off, and pinning to P-cores

ComputerBase measured the first idea in its 12900K gaming test in 2021. With the E-cores switched off, the average across its games rose by 1 percent and the percentiles stayed the same. A few games ran faster with P-cores only, but the advantage was "meistens gering", mostly small, and the conclusion was that switching off the E-cores for games in general is "nicht ratsam", not advisable. That is one processor, one game set and one year, so measure on yours.

Pinning a game to some cores with affinity has a documented cost. Microsoft's scheduling documentation says thread affinity "should generally be avoided, because it can interfere with the scheduler's ability to schedule threads effectively across processors", and that "an appropriate use of thread affinity is testing each processor". Intel's guide adds that hard affinities force the OS "to ignore any advice it receives from the Intel Thread Director". Process affinity is also inherited by child processes, Microsoft notes, so a restricted launcher can pass the restriction on to a game it starts.

If you want to try it, treat it as a test: GPU not at 100% shows where Task Manager displays a game's affinity and what a forgotten mask looks like. Run the same scene with and without the restriction, then give the game every processor again.

What does not help

• Staying on Windows 10 for the scheduler. It is out of support, and Intel ties Thread Director to the Windows 11 updates.
• Switching E-cores off as a general fix. ComputerBase's measurement above concluded against it.
• A permanent affinity mask. It overrides Thread Director's advice and carries over to child processes.
• Expecting APO on a CPU or game that is not on Intel's lists.
• Judging by feel. Measure the same scene before and after one change; reading the benchmark covers how.

Related

• Ryzen X3D with two CCDs: chipset driver, Game Bar, core parking
• Intel 13th and 14th gen crashes in games
• GPU not at 100%
• Processor power settings
• Reading the benchmark