README

The ASUS gaming laptop ACPI firmware DPC stall

 Status update (December 2025): The original periodic ACPI/DPC stall described in this write-up is fixed. ASUS shipped a UEFI update that rewrites the ACPI ECLV routine (the sleeps and the self-rearm are gone) and also includes other ACPI power-management optimizations.

 What changed

ASUS updated the firmware's ACPI EC/GPE event handling. The main change is in the ECLV method. It no longer sleeps inside the event-processing loop, and it no longer re-arms itself when it hits its internal "time budget".

 AML diff (old vs new)

diff
 Method (ECLV, 0, NotSerialized)
 {
-    // Main loop - continues while events exist OR sleep events are pending
-    // AND we haven't exceeded our time budget (TI3S = 0x78)
-    {
-        TI3S = Zero
-        If (EEV0 == Zero)
-        {
-            EEV0 = 0xFF
-        }
-    }
 }


 Updated LatencyMon results (G533ZW, UEFI 327)




 The problem

You own a high-end ASUS ROG laptop, maybe a Strix, Scar or Zephyrus. The specs are good: an RTX 30/40 series GPU, a top Intel CPU and plenty of RAM. But it stutters on basic tasks like watching a YouTube video, audio crackles and pops on Discord calls, and the mouse cursor freezes for a split second.

You've probably tried the usual fixes:
- Updating every driver, multiple times.
- Doing a clean reinstall of Windows.
- Disabling every power-saving option.
- Manually tweaking processor interrupt affinities.
- Following long multi-step guides from Reddit threads.
- Even installing Linux, where the problem is still there.

If none of that worked, it's because the problem was never in the operating system or a driver. It was in the laptop's firmware (UEFI), and ASUS has since shipped a UEFI update that fixes the original periodic ACPI/DPC stall described below.

 Initial symptoms and measurement

The first thing to run for symptoms like these is LatencyMon. On an affected ASUS Zephyrus M16 it reports:


CONCLUSION
Your system appears to be having trouble handling real-time audio and other tasks. 
You are likely to experience buffer underruns appearing as drop outs, clicks or pops.

HIGHEST MEASURED INTERRUPT TO PROCESS LATENCY
Highest measured interrupt to process latency (μs):   65,816.60
Average measured interrupt to process latency (μs):   23.29

HIGHEST REPORTED ISR ROUTINE EXECUTION TIME
Highest ISR routine execution time (μs):              536.80
Driver with highest ISR routine execution time:       ACPI.sys

HIGHEST REPORTED DPC ROUTINE EXECUTION TIME  
Highest DPC routine execution time (μs):              5,998.83
Driver with highest DPC routine execution time:       ACPI.sys


ACPI.sys has both the highest ISR and the highest DPC execution time. The per-CPU numbers narrow it down further:


CPU 0 Interrupt cycle time (s):                       208.470124
CPU 0 ISR highest execution time (μs):                536.804674
CPU 0 DPC highest execution tim

Top issues

Discussions