windows registry reference

Windows performance settings reference

Exact registry paths, valid values, Windows defaults, and a straight answer on whether each one is worth changing.

Last updated

What is this?

A reference for the Windows settings that gaming and performance guides tell people to change. Each page gives the exact registry path, the valid values, the documented default, what Windows actually does with the setting, and whether changing it is worth doing. Several of these settings are documented by Microsoft as unused or clamped, which means the advice repeated about them across thousands of forum posts has never worked. Those pages say so.

It is written to be usable without buying anything. Every setting documented here can be changed by hand, for free, and each page says plainly whether doing so is worth it.

Looking for the complete list?

Every change the application makes, with its exact registry path, is in one table: every change the application makes. The pages below go deeper on the settings worth understanding properly.

Three findings worth knowing before you edit anything

  • Setting SystemResponsiveness to 0 does nothing. Microsoft's MMCSS documentation states that values below 10 are clamped to 20 — the default. The registry will show 0; the scheduler ignores it. Full detail.
  • GPU Priority in the MMCSS Games key is not used. Microsoft's reference has described it as "not yet used" for years. The same documentation says SFIO Priority is not used either. Full detail.
  • IRPStackSize is a file-server setting. It governs SMB file sharing and has nothing to do with gaming latency, despite appearing in gaming tweak lists for twenty years. Full detail.

CPU scheduling and thread priority

Win32PrioritySeparation
The foreground thread quantum setting, and why 0x26 usually changes nothing on a desktopSystemResponsiveness
The MMCSS reservation, and why setting it to 0 does nothingThe MMCSS Games task profile
GPU Priority, Priority, Scheduling Category, SFIO Priority — and which of them Windows actually readsGlobalTimerResolutionRequests
The Windows 10 2004 timer change, and what it means for latency tools

Network stack

NetworkThrottlingIndex
The multimedia network throttle, when it applies, and when it is irrelevantNagle's algorithm (TcpAckFrequency and TCPNoDelay)
What Nagle actually does, and why disabling it is not a ping fixIRPStackSize
A file-server setting that has nothing to do with gaming latencyChecksum offload, RSS and Large Send Offload
What offloading moves onto the network card, and why turning it off is usually wrong

Mouse, keyboard and input latency

Mouse acceleration and the pointer precision curve
MouseSpeed, MouseThreshold1, MouseThreshold2 and SmoothMouseXCurveUSB selective suspend and device polling
Power management on the port your mouse is plugged into

GPU and display

Game DVR, Game Bar and Fullscreen Optimizations
Background recording, the capture pipeline, and what fullscreen optimizations really changeHardware-accelerated GPU scheduling (HwSchMode)
What moving scheduling onto the GPU changes, and why the answer is 'test it'

Power management

PowerThrottlingOff
Windows power throttling, which processes it targets, and when disabling it mattersFast Startup (HiberbootEnabled) and hibernation
Why 'shut down' does not fully shut down, and when that causes problemsCore parking and processor performance states
Minimum and maximum processor state, core parking, and what the power plan already does

Memory management

LargeSystemCache
A server memory policy that usually hurts desktopsDisablePagingExecutive
Keeping kernel code resident, and what that is actually worthSvcHostSplitThresholdInKB
Why Windows 10 has so many svchost.exe processes, and what changing it costsThe Windows page file
Why disabling it causes crashes, and what it is actually for

Filesystem and storage

NtfsDisableLastAccessUpdate
The last-access timestamp, and why Windows already manages it for youEnablePrefetcher and SysMain
Prefetch, Superfetch and the SSD myth

Desktop shell responsiveness

MenuShowDelay and StartupDelayInMSec
Two shell delays that are real, deliberate, and safe to change

Security mitigations

Disabling Spectre and Meltdown mitigations
A real performance setting with a real security cost — read this one carefully

Telemetry and privacy

AllowTelemetry
The diagnostic data level, and why 0 does not mean off on Home and Pro

Before you change anything

Create a System Restore Point first. Change one setting at a time and test between changes, because applying twenty at once and then noticing instability a week later leaves you with no way to identify which one caused it. That is the single most common way registry tuning goes wrong, and it is entirely avoidable.

If a setting's page says it is not worth changing, that is the recommendation. Leaving a default alone is a legitimate outcome.