{"id":1717927,"date":"2022-09-15T15:43:00","date_gmt":"2022-09-15T15:43:00","guid":{"rendered":"http:\/\/www.sweetwater.com\/sweetcare\/?post_type=articles&p=1717927"},"modified":"2025-04-23T14:52:46","modified_gmt":"2025-04-23T18:52:46","slug":"solving-dpc-latency-issues","status":"publish","type":"articles","link":"https:\/\/www.sweetwater.com\/sweetcare\/articles\/solving-dpc-latency-issues\/","title":{"rendered":"Solving DPC Latency Issues"},"content":{"rendered":"\n

In this article,\nwe\u2019ll discuss what DPC latency is, some of the common symptoms, and how to\ntroubleshoot any issues you may encounter. Follow the sections below to get\nstarted.<\/p>\n\n\n\n

  1. What is DPC latency?<\/strong><\/a><\/li>
  2. How to check DPC latency on Windows<\/a><\/strong><\/li>
  3. How to use LatencyMon<\/a><\/strong><\/li><\/ol>\n\n\n\n

    What is DPC latency?<\/h2>\n\n\n\n

    Many audio problems on a computer can be caused by high DPC latency. But what is DPC latency? DPC stands for Deferred Procedure Call. In its purest form, it is the part of your Windows system that handles driver efficiency. If a driver takes longer than usual to process, it may prevent other drivers from being processed in time (latency<\/strong><\/a>). If you\u2019ve tried uninstalling and reinstalling drivers, tried different ports and cables, and you\u2019re still having issues, checking the DPC latency can help narrow down the core issue. Some common symptoms of high DPC latency on your Windows PC can be stuttering video playback or inconsistent performance with your peripherals (mouse, keyboard). However, the most common symptoms are audio dropouts, clicks, and popping.<\/p>\n\n\n\n


    \nWhen you have\nhigh DPC latency on Windows, your computer\u2019s audio drivers (either built-in\nsystem soundcards or external audio interfaces) won\u2019t respond in time. This\ncauses clicks, pops, distortion, and dropouts. In some cases, DPC latency can\nalso cause a BSOD (Blue Screen of Death). <\/p>\n\n\n\n\n\n\n\n

    How to check DPC latency on Windows <\/h2>\n\n\n\n

    Depending on what version of Windows you\u2019re currently using, there are a few programs that can help show you how to check and diagnose DPC latency. If you are running Windows 7 or higher, then we recommend using LatencyMon<\/a> by Resplendence. This latency monitoring software will tell you if there is a DPC latency issue, and it will also tell you which driver or drivers are causing the latency.<\/p>\n\n\n\n

    The only option for checking DPC latency issues on Windows XP or Vista systems is the DPC Latency Checker<\/a> by SysCon. This utility will only tell you if you have a DPC latency issue; it will not tell you what is causing it.<\/p>\n\n\n\n

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    \n

    Download LatencyMon<\/a><\/p>\n<\/div>\n\n\n\n

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    DPC Latency Checker<\/a> <\/p>\n<\/div>\n<\/div>\n\n\n\n\n\n\n\n

    How to use LatencyMon<\/h2>\n\n\n\n

    LatencyMon will\nshow the status of the latency issues in the Report Area<\/strong>. Once the bars\nat the bottom start to increase, you\u2019ll receive a message in the Report Area (top\npart of the window)that turns red once there are problems. The lower\nsection of the LatencyMon window will show you the problematic drivers. This\nmakes it very easy to narrow down what the problematic driver is. Let\u2019s discuss\nhow to use LatencyMon.<\/p>\n\n\n\n

    Some of the most\ncommon errors we see when running LatencyMon are with USBPORT.sys, NDIS.sys, or\nTCP\/IP.sys, and depending on your graphics card, nvlddmkm.sys. You\u2019ll likely\nreceive the following error message and possible solutions to remedy the issue:<\/p>\n\n\n\n

    \u201cYour system appears to be having trouble handling real-time audio and other tasks. You are likely to experience <\/em>buffer<\/em><\/a> underruns appearing as dropouts, clicks, or pops. One problem may be related to power management, disable <\/em>CPU<\/em><\/a> throttling settings in Control Panel and BIOS setup. Check for BIOS updates.\u201d<\/em><\/p>\n\n\n\n

    1. Press the Play<\/strong> button to begin monitoring your computer.<\/li>
    2. We recommend letting the monitor run for at least a few minutes or so for a more detailed performance scan.<\/li>
    3. If the bars in the \u201cHighest reported ISR routine execution time\u201d and\/or \u201cHighest reported DPC routine execution time\u201d sections begin to turn orange or red, take note of what\u2019s listed in the brackets, e.g., [USBPORT.sys].<\/li>
    4. Click the Drivers <\/strong>tab, which displays the driver file that\u2019s currently running on your Windows PC (including background services).<\/li>
    5. Click DPC Count <\/strong>to sort the DPC from highest to lowest, and take note of that driver. <\/li>
    6. If it\u2019s a driver you recognize, such as your audio interface\u2019s driver, and has the highest DPC\/ISR count, then uninstall that driver and rerun the test.