Very High DPC latency, windows too slow RRS feed

  • Question

  • good day to all

    I have a problem with a used laptop which is too slow, in everything, booting, loading even screen redraws like 1 fps... booting to desktop would be like 20 minute or more.

    Its a intel dual core laptop with 2gb ram.

    I cant add screenshot from dpc latency checker yet but the numbers can reach 16000µs

    I check with latencymon and this is the result, please advise..

    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. One problem may be related to power management, disable CPU throttling settings in Control Panel and BIOS setup. Check for BIOS updates. 
    LatencyMon has been analyzing your system for  0:06:35  (h:mm:ss) on all processors.

    Computer name:                                        WIN7PRO-PC
    OS version:                                           Windows 7 , 6.1, build: 7600 (x86)
    Hardware:                                             Satellite L500, TOSHIBA, KSWAA
    CPU:                                                  GenuineIntel Pentium(R) Dual-Core CPU T4400 @ 2.20GHz
    Logical processors:                                   2
    Processor groups:                                     1
    RAM:                                                  2042 MB total

    Reported CPU speed:                                   2194.0 MHz
    Measured CPU speed:                                   785.0 MHz (approx.)

    Note: reported execution times may be calculated based on a fixed reported CPU speed. Disable variable speed settings like Intel Speed Step and AMD Cool N Quiet in the BIOS setup for more accurate results.

    The interrupt to process latency reflects the measured interval that a usermode process needed to respond to a hardware request from the moment the interrupt service routine started execution. This includes the scheduling and execution of a DPC routine, the signaling of an event and the waking up of a usermode thread from an idle wait state in response to that event.

    Highest measured interrupt to process latency (µs):   267691.037070
    Average measured interrupt to process latency (µs):   385.916645

    Highest measured interrupt to DPC latency (µs):       514.207190
    Average measured interrupt to DPC latency (µs):       171.246478

    The SMI, IPI and CPU stalls value represents the highest measured interval that a CPU did not respond while having its maskable interrupts disabled.

    Highest measured SMI or CPU stall (µs)                22.864022

    Interrupt service routines are routines installed by the OS and device drivers that execute in response to a hardware interrupt signal.

    Highest ISR routine execution time (µs):              154.987694
    Driver with highest ISR routine execution time:       ataport.SYS - ATAPI Driver Extension, Microsoft Corporation

    Highest reported total ISR routine time (%):          23.448343
    Driver with highest ISR total time:                   ACPI.sys - ACPI Driver for NT, Microsoft Corporation

    Total time spent in ISRs (%)                          12.444509

    ISR count (execution time <250 µs):                   1635368
    ISR count (execution time 250-500 µs):                0
    ISR count (execution time 500-999 µs):                0
    ISR count (execution time 1000-1999 µs):              0
    ISR count (execution time 2000-3999 µs):              0
    ISR count (execution time >=4000 µs):                 0

    DPC routines are part of the interrupt servicing dispatch mechanism and disable the possibility for a process to utilize the CPU while it is interrupted until the DPC has finished execution.

    Highest DPC routine execution time (µs):              761.572015
    Driver with highest DPC routine execution time:       ACPI.sys - ACPI Driver for NT, Microsoft Corporation

    Highest reported total DPC routine time (%):          24.936698
    Driver with highest DPC total execution time:         ACPI.sys - ACPI Driver for NT, Microsoft Corporation

    Total time spent in DPCs (%)                          36.711555

    DPC count (execution time <250 µs):                   1800603
    DPC count (execution time 250-500 µs):                0
    DPC count (execution time 500-999 µs):                228981
    DPC count (execution time 1000-1999 µs):              0
    DPC count (execution time 2000-3999 µs):              0
    DPC count (execution time >=4000 µs):                 0

    Hard pagefaults are events that get triggered by making use of virtual memory that is not resident in RAM but backed by a memory mapped file on disk. The process of resolving the hard pagefault requires reading in the memory from disk while the process is interrupted and blocked from execution.

    NOTE: some processes were hit by hard pagefaults. If these were programs producing audio, they are likely to interrupt the audio stream resulting in dropouts, clicks and pops. Check the Processes tab to see which programs were hit.

    Process with highest pagefault count:                 mxup.exe

    Total number of hard pagefaults                       276
    Hard pagefault count of hardest hit process:          222
    Highest hard pagefault resolution time (µs):          5741232.835916
    Total time spent in hard pagefaults (%):              9.015841
    Number of processes hit:                              8

    CPU 0 Interrupt cycle time (s):                       345.138708
    CPU 0 ISR highest execution time (µs):                154.987694
    CPU 0 ISR total execution time (s):                   44.218322
    CPU 0 ISR count:                                      812673
    CPU 0 DPC highest execution time (µs):                761.572015
    CPU 0 DPC total execution time (s):                   216.864622
    CPU 0 DPC count:                                      1432924
    CPU 1 Interrupt cycle time (s):                       170.272522
    CPU 1 ISR highest execution time (µs):                134.993163
    CPU 1 ISR total execution time (s):                   54.185136
    CPU 1 ISR count:                                      822695
    CPU 1 DPC highest execution time (µs):                589.407475
    CPU 1 DPC total execution time (s):                   73.427595
    CPU 1 DPC count:                                      596660

    • Edited by Mangkook Sunday, August 4, 2013 11:14 PM edit
    Sunday, August 4, 2013 10:35 PM


All replies

  • Hi Mangkook,

    Based on my understanding, your computer is running slowly and you would like to optimize Windows better performance. Right?

    Please try the following methods to solve this issue:

    Method 1: Try the performance troubleshooter

    1. Click Start, and click Control Panel.
    2. Type troubleshooter in the Search box.
    3. Click Check for performance issues under System and Security.

    Method 2: Run the troubleshooter and check.

    Please review this article to learn how to Fix Windows system performance problems on slow Windows computers:


    Method 3: Safe mode and clean boot

    1. Start your computer in safe mode to check if the accounts can work. As for how to start into safe mode, please review this article Start your computer in safe mode.
    2. Perform a clean boot.

    A clean boot helps to verify if any third party application services or startup item is causing this issue. For your information, please review this KB article to put the computer in clean boot:

           How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7

    Note: Make sure you put the computer back to Normal Startup once you are done with the troubleshooting.

    Method 4: Run a virus/malware scan of your entire system.

    You may run online virus scan from the following link:


    Note: Make sure you select the correct version of the operating system before downloading the scanner)

    For your information, please review the following article Optimize Windows for better performance ro learn more methods to optimize your computer:



    Lany Zhang

    Monday, August 5, 2013 2:00 AM
  • Follow my guide an and upload the xperf trace file:

    "A programmer is just a tool which converts caffeine into code"

    Monday, August 5, 2013 5:10 AM
  • The DCP latency in windows is a very well known problem. I think Microsoft should seriously work on this. I think is really useless to reply by the "always same standard response" that does not really fix anything. I feel joked by that kind of response. You should build a better release. Full stop.

    Dario de Judicibus

    Monday, October 21, 2019 8:45 AM