DPC latency is the performance problem most people have never heard of — and it’s behind a huge share of “mysterious” issues: audio that crackles and pops, a mouse cursor that jumps, video that micro-stutters despite a fast GPU, dropouts in music production. The symptoms feel like hardware failure, but the cause is almost always one misbehaving driver holding the system hostage for milliseconds at a time.

The fix process is beautifully scientific: measure with LatencyMon, identify the offending driver by name, update/disable/reconfigure it, re-measure. No guesswork. This guide walks through exactly that. For the related kernel-CPU issue, see fixing ntoskrnl.exe high CPU ; for general game stutter, Windows 11 stutter fixes .

Why this happens

  • Buggy network drivers: Wi-Fi drivers are the number-one DPC latency offenders on laptops — power-saving polling gone wrong.
  • Storage driver issues: Outdated Intel RST or NVMe drivers with long interrupt handlers.
  • GPU driver power management: Drivers slow to switch power states, stalling the system during transitions.
  • USB controller drivers: Problematic USB 3.x drivers, especially with certain docks and peripherals attached.
  • Power management transitions: CPU C-state and PCIe link-state changes adding latency spikes.
  • Antivirus filter drivers: Real-time AV hooking I/O paths with expensive handlers.
  • Failing hardware spamming interrupts: A dying device generating interrupt storms (rare, but real).

How to fix it

Work through these in order — diagnose first, then act.

Fix 1: Measure with LatencyMon

Get the numbers and the name.

  1. Download LatencyMon (Resplendence, free) — run it as Administrator and click the play button to start monitoring.
  2. Let it run for 10 minutes during normal use (include the activity that glitches — play audio, move the mouse, game briefly).
  3. Read the Main tab: Highest reported DPC routine execution time and which driver caused it — LatencyMon names names (e.g., ndis.sys, storport.sys, nvlddmkm.sys, tcpip.sys).
  4. Check the Drivers tab sorted by DPC count and Highest execution — the top offender is your target. Screenshot everything.
  5. Note the pattern: constant high DPC = a driver always misbehaving; periodic spikes = power-state transitions or polling (Fixes 3–4).

Fix 2: Update the offending driver

The fix for the majority of cases.

  1. Identify the driver file from LatencyMon (e.g., Netwtw10.sys = Intel Wi-Fi, rtwlanu.sys = Realtek, storahci.sys = storage).
  2. Get the update from the right source: your laptop vendor’s support site first (Dell , HP’s support site, Lenovo’s support site), then the chip vendor (Intel’s driver assistant ) if the OEM version is old.
  3. For Wi-Fi offenders specifically: update both the Wi-Fi driver and Bluetooth driver — they share the radio and the driver package, and Bluetooth’s polling is a frequent hidden contributor.
  4. For GPU offenders (nvlddmkm.sys, amdkmdag.sys): clean-install the latest driver (DDU in Safe Mode, then fresh install) — DPC issues often come from driver upgrades layered over old remnants.
  5. Re-run LatencyMon for 10 minutes after each driver update — verify the specific offender’s numbers dropped, don’t just assume.

Fix 3: Tame Wi-Fi power saving (the classic)

The number-one DPC latency fix on laptops.

  1. Device Manager > Network adapters > your Wi-Fi adapter > Properties > Advanced tab — set Power Saving Mode / Roaming Aggressiveness to Maximum Performance; disable U-APSD / WMM-PS power-save features.
  2. Power Management tab (same device) — uncheck Allow the computer to turn off this device to save power. The power-state transitions of the Wi-Fi radio are a legendary DPC spike source.
  3. powercfg.cpl > advanced settings > Wireless Adapter Settings > Power Saving Mode > Maximum Performance (plugged in).
  4. Re-run LatencyMon — Wi-Fi-related DPC spikes often collapse immediately after these changes.
  5. If you use the laptop mostly docked on Ethernet, disable the Wi-Fi adapter entirely when docked (Device Manager > right-click > Disable device) — a disabled radio generates zero DPC.

Fix 4: Disable CPU power-state transitions (diagnostic)

Proving whether C-states are the spiker.

  1. Periodic DPC spikes (every few seconds, rhythmic) scream power-state transitions — CPU C-states or PCIe link-state changes.
  2. Test: powercfg.cpl > advanced > Processor power management > Minimum processor state = 100% (plugged in) — this keeps the CPU from deep-sleeping between tasks.
  3. Also set PCI Express > Link State Power Management = Off.
  4. Re-run LatencyMon — if spikes vanish, power management was the cause. You can then experiment with intermediate settings (minimum 50%, link-state moderate) to find the sweet spot between latency and battery.
  5. For DAW/audio work, many professionals run a dedicated high-performance power plan with these disabled permanently — latency matters more than battery when recording.

Fix 5: Address storage and USB offenders

For storport/USB-related DPC.

  1. If LatencyMon blames storport.sys, stornvme.sys, or similar: update chipset and storage drivers (Intel RST, AMD chipset) from the vendor.
  2. Check SSD firmware — storage DPC issues sometimes trace to firmware-level interrupt behavior; update via the maker’s utility.
  3. For USB offenders (USBXHCI.sys): update chipset drivers, and test with USB peripherals disconnected — a specific device (often an audio interface or dock) can trigger the controller’s bad behavior.
  4. In Device Manager > Universal Serial Bus controllers, check each hub’s Power Management — uncheck Allow the computer to turn off this device for the xHCI controller as a test.
  5. If a USB audio interface is involved: try different USB ports (different controllers), and check the interface maker’s site for driver/firmware updates — audio interfaces are exquisitely sensitive to DPC.

Fix 6: Check antivirus and filter drivers

The invisible interrupt tax.

  1. LatencyMon blaming fltMgr.sys or AV filter drivers (names containing your AV vendor) means file-system filter overhead.
  2. Test: temporarily disable real-time protection and re-run LatencyMon — a dramatic drop confirms AV involvement.
  3. The fix isn’t disabling AV permanently — it’s updating the AV (filter driver fixes ship regularly) or switching to a product with lighter filters. Windows Defender’s filters are generally well-behaved when updated.
  4. Also audit other filter drivers: VPN clients, disk encryption (non-BitLocker), and backup software all install filters — LatencyMon’s Drivers tab shows their DPC contribution; disable suspects one at a time.
  5. Keep only the filters you need — each one adds latency to every I/O operation, and they stack.

Fix 7: BIOS update and hardware verdict

When drivers don’t explain it.

  1. Check your BIOS version against the vendor’s latest — BIOS/UEFI updates regularly fix interrupt routing, ACPI, and power-management issues that manifest as DPC latency. Follow the vendor’s flash instructions with the charger connected.
  2. In BIOS setup, look for Intel SpeedStep / Speed Shift, C-states, and ASPM options — disabling deep C-states here is the firmware-level version of Fix 4 (use for testing; re-enable selectively).
  3. If one specific device (a failing drive, a flaky Wi-Fi card) generates interrupt storms, LatencyMon shows its driver with astronomical DPC counts — Device Manager > disable the device as a test; if latency normalizes, the hardware is the problem.
  4. For persistent unexplained DPC after all software fixes: run the vendor’s hardware diagnostics (Dell F12 diagnostics, Lenovo Vantage hardware scan, HP UEFI diagnostics).
  5. True hardware DPC causes are rare — but when LatencyMon keeps naming the same driver across three driver versions and two Windows installs, the device underneath is telling you something. Microsoft documents interrupt/latency troubleshooting on the Windows support hub .

Closing

High DPC latency is the rare performance problem with a perfect diagnostic loop: LatencyMon names the driver, you update or reconfigure that driver, LatencyMon confirms the fix. No guessing, no registry voodoo — just measurement and targeted action. The audio stops crackling, the mouse stops jumping, and the stutter you couldn’t explain finally has a name and a fix. For a problem this annoying, the solution is refreshingly scientific.

Frequently asked questions

What is DPC latency in simple terms?
DPC (Deferred Procedure Call) latency measures how long drivers take to finish their interrupt work. When a driver takes too long — say, 2 milliseconds instead of 0.05 — everything else in the system waits, causing audio crackles, mouse cursor jumps, and video micro-stutters. It’s measured in microseconds; spikes above 1000µs are where humans start noticing problems.
What DPC latency numbers are good or bad?
Under 200µs average with rare spikes under 500µs is excellent. Occasional spikes to 1000µs are tolerable for most use. Sustained spikes above 2000µs cause audible audio glitches; above 5000µs you’ll see mouse and UI stutter too. For professional audio work (DAWs), you want everything under 500µs — that’s why musicians obsess over this metric.
Can DPC latency cause game stuttering?
Yes — it’s a classic hidden cause of micro-stutter that FPS counters don’t explain. A driver holding the system for milliseconds at a time makes frames arrive late even when the GPU is fast. If your games stutter despite good FPS and the usual fixes failed, DPC latency from a network, storage, or power-management driver is a prime suspect.
Is high DPC latency a hardware or software problem?
Overwhelmingly software — specifically, buggy or outdated drivers. The hardware is fine; a driver is just taking too long in its interrupt handler. That’s good news: driver updates, disabling the offending device, or changing power settings usually fix it without touching hardware. True hardware-caused DPC issues (failing devices spamming interrupts) are rare.