System Interrupts process constantly causing high CPU usage (30-40%) in Task Manager

Question

Hey team, my PC has been stuttering even while just sitting idle on the desktop. When I sort Task Manager by CPU utilization, a process called "System Interrupts" is constantly consuming between 30% and 40% of my processor. I know this usually means a hardware or driver conflict, but I don't know how to track down which specific device is spamming the CPU with requests.

Answer 1

Hi,Cooper

Here’s the English translation of the analysis on the most likely causes for high CPU usage by “System Interrupts”:

Most Likely Causes (ranked from highest probability to lowest)

1. Network Adapter Driver Issues (over 50% of cases)

· Typical scenarios:

· A Wi‑Fi or certain Realtek/Qualcomm Ethernet adapter that keeps firing interrupts even when idle (e.g., constantly scanning for networks, processing wake‑on‑LAN packets).

· Hardware offloading features (e.g., Large Send Offload, ARP offload) that are incompatible with the driver.

· “Energy Efficient Ethernet” or “Allow the computer to turn off this device to save power” enabled.

· Quick test: Disable your network adapters (both Wi‑Fi and Ethernet) in Device Manager. If the “System Interrupts” CPU usage drops immediately, you’ve found the culprit.

2. Audio / Sound Driver (especially Realtek HD Audio)

· Typical scenarios: An outdated or buggy audio driver that causes the audio system’s timer or DSP to trigger constant interrupts, even when no sound is playing and the system is idle.

· Quick test: Disable your sound card under “Sound, video and game controllers” in Device Manager.

3. USB Controllers or BIOS Power Management (C‑States)

· Typical scenarios:

· Deep C‑states (C6/C7/C10) enabled in BIOS – some USB devices (keyboard, mouse, webcam) generate excessive interrupts when entering/exiting sleep.

· Faulty USB 3.0 controller drivers.

· Quick test:

· Enter BIOS/UEFI and temporarily disable C‑States (set to “Disabled” or “C1 only”).

· Or, in Device Manager, disable USB Root Hubs one by one under “Universal Serial Bus controllers”.

Other Possibilities (less frequent but worth checking)

· SATA / PCIe AHCI driver – often accompanied by unusual disk activity. Check your disk health with CrystalDiskInfo.

· Third‑party antivirus / firewall – though they don’t directly show as “System Interrupts”, their hook drivers can cause DPC storms. Try a clean boot.

✅ Immediate Actions You Can Take

1. First, disable your network adapter (especially Wi‑Fi) and then your audio driver. In many cases the problem disappears after these two steps.
2. If that doesn’t help, run LatencyMon for a few minutes. Look at the Drivers tab – sort by “DPC Count” or “Highest Execution”. The top .sys file (often ndis.sys for network, portcls.sys for audio, or USBPORT.sys for USB) will point you directly to the problematic device.

Answer 2

Hi Cooper,

“System Interrupts” consuming 30–40% CPU means a device driver is flooding the processor with hardware interrupts. The fastest way to pinpoint it is to run a Windows Performance Recorder (WPR) trace with CPU and interrupts enabled, then analyze it in Windows Performance Analyzer (WPA) to see which .sys driver is responsible. Update BIOS and chipset drivers first, then disable devices in Device Manager one at a time (Wi-Fi, Bluetooth, audio, USB) to see if usage drops. If WPA highlights drivers like ndis.sys or usbport.sys, reinstall or replace the associated hardware driver. If driver updates don’t resolve it, failing hardware is the likely cause.

Harry.