If you’ve ever experienced audio dropouts, crackling, stuttering in games, or unreliable real-time performance on Windows 11, DPC latency is likely the culprit. DPC stands for Deferred Procedure Call — a mechanism Windows uses to handle hardware interrupt processing. When a driver takes too long to process a DPC, it delays everything else, causing the audible glitches and frame timing issues you feel during gaming or music production. LatencyMon is the tool that identifies exactly which drivers are causing the problem.

Download and Install LatencyMon

LatencyMon is free and made by Resplendence Software. Download it from resplendence.com/latencymon. It’s a standalone executable — no installation required. Run it as Administrator for accurate readings.

Running a Latency Test

Open LatencyMon and click the green Play button to start monitoring. Let it run for at least 5–10 minutes while replicating the conditions that cause your problem (playing audio, gaming, running your DAW).

The main screen shows:

Highest measured interrupt to process latency — the worst single spike recorded
Average ISR routine execution time — how long Interrupt Service Routines take
Average DPC routine execution time — how long Deferred Procedure Calls take

For real-time audio (DAWs, ASIO), you want DPC latency below 1,000 microseconds consistently. For gaming, below 2,000 µs is acceptable. If you’re seeing spikes above 10,000 µs, you have a significant driver problem.

Reading the Results

Switch to the Drivers tab — this is the most useful view. It lists every driver ranked by their total DPC execution time. The columns to focus on:

Column	Meaning
DPC Count	Total number of DPCs issued
Total Time	Cumulative time spent in DPCs
Highest Execution	Worst single spike
Module	The driver file causing issues

Common offenders:

ndis.sys — network driver framework (often Wi-Fi drivers)
wdf01000.sys — Windows Driver Framework (generic, look at the process column)
ks.sys — kernel streaming (audio)
storport.sys — storage driver
nvlddmkm.sys — NVIDIA GPU driver
HDAudio.sys — HD Audio
dxgkrnl.sys — DirectX graphics kernel

Fixing Common DPC Latency Problems

Network Drivers (ndis.sys)

Wi-Fi adapters are the most frequent cause of DPC spikes. Try these fixes:

Open Device Manager → Network Adapters → your Wi-Fi adapter → Properties → Advanced tab
Disable Interrupt Moderation (set to Disabled)
Set Transmit Buffers and Receive Buffers to maximum
Disable Power Management — uncheck “Allow the computer to turn off this device to save power”
Consider switching to a wired Ethernet connection while testing — if latency drops dramatically, the Wi-Fi driver is your problem

Update your network drivers directly from the manufacturer (Intel, Realtek, Qualcomm) rather than Windows Update.

NVIDIA GPU Driver (nvlddmkm.sys)

NVIDIA drivers can cause latency spikes particularly during shader compilation or when swapping between power states. Try:

In NVIDIA Control Panel → Manage 3D Settings → set Power Management Mode to “Prefer Maximum Performance”
Disable NVIDIA Container and NVIDIA Telemetry Container services in Task Manager → Services
Use DDU (Display Driver Uninstaller) to perform a clean driver install with the latest Game Ready Driver

Audio Drivers

If HDAudio.sys or audio-related drivers appear high in the list:

In Device Manager, update your audio driver from the motherboard manufacturer’s website (not Microsoft’s generic HDA driver)
If using ASIO for music production, switch to a dedicated audio interface with ASIO4ALL or native ASIO drivers
Disable audio enhancements: right-click the speaker icon → Sound Settings → your output device → Properties → Enhancements → disable all

USB Drivers (usbport.sys, usbehci.sys)

USB polling can cause latency spikes. In LatencyMon, if USB drivers appear:

Try unplugging USB devices one at a time to isolate the culprit
USB audio interfaces, certain gaming mice, and hubs can cause this
Move devices to different USB controllers (try USB 2.0 vs 3.0 ports)

Power Management and Timer Resolution

Windows 11 defaults to a system timer resolution of 15.6ms, which causes coarse scheduling. Many real-time applications (DAWs, competitive games) request a 1ms timer, but this can cause latency issues if conflicting:

# Check what timer resolution is currently set
powercfg /query SCHEME_CURRENT SUB_SLEEP STANDBYIDLE

Install TimerResolution by Lucas Haber to force 0.5ms resolution while gaming:

TimerResolution.exe /SetMaxResolution

Also enable the High Performance power plan:

powercfg /setactive 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c

Checking the Process Tab

LatencyMon’s Processes tab shows which running applications are contributing to latency. Look for:

Antivirus engines during active scanning (schedule scans for off-hours)
Browser GPU processes
Backup software

Verifying the Fix

After making changes, restart your PC and run LatencyMon again for 10 minutes under the same conditions. The Highest measured interrupt to process latency number should be dramatically lower. For most users, fixing the primary offending driver (usually network or GPU) reduces spikes from 50,000+ µs to under 1,000 µs.

For gaming specifically, complement LatencyMon results with RTSS (RivaTuner Statistics Server) frame time graphs — you should see tighter frame time consistency after addressing DPC latency issues.

LatencyMon Guide: Fix DPC Latency on Windows 11