How to Diagnose and Fix High DPC Latency Issues with WPA (Windows Vista/7/8)

This tutorial will show you how to identify drivers causing high Deferred Procedure Call (DPC) latencies. Spikes of high DPC latency can cause a computer to slow to a crawl for a few seconds before speeding up again in super-speed to catch up, then repeating a number of seconds later. During the few seconds of slowness (high latency spike), you may notice jerky and erratic mouse movement, poor quality, stuttering, audio, and pausing and skipping in real time video playback. If these symptoms sound familiar, read on.

The technique outlined below will work on Windows 7 and Windows 8. It will not work on Windows XP, but an alternative for Step II has been briefly outlined at the bottom of this tutorial for Windows Vista.

In addition, this technique is fairly technically advanced. Although it should be perfectly possible for anyone to complete provided you follow carefully the instructions given, if you require further clarification of any particular steps, or run into any sort of difficulties, please do not hesitate to ask us for help.


Step I (optional): Making a Quick Diagnosis:
[This part is not yet possible on Windows 8 computers. If you are using Windows 8, please skip ahead to Step II]

This step will allow you to quickly and easily determine whether or not high DPC latencies are indeed a problem on your computer. It is not necessary to perform this step, since it will not show you the cause of any DPC latency spikes it does find. Step II will be used to determine the cause any of such problems, and so you may wish to skip ahead to Step II now.

1. Download and run DPC Latency Checker from this website: DPC Latency Checker

2. Allow it to run until you have experienced a period of lagging and computer slowness. It is important to allow the program to run through such a time period in order to make a proper diagnosis. Having it running only whilst the computer is performing normally is not nearly as effective.

3. Analyze the graph for a large spike into the reds. A healthy graph will remain in the green section, and will look similar to this:
1.PNG

A graph containing spikes into the red (indicative of a DPC latency problem) will look similar to this:
2.png
Now identify whether or not you have a DPC Latency problem using the graphs given above as a reference. If you do, continue on to Step II to identify the cause of this problem.



Step II (if necessary): Identifying the Cause:
[This technique is not possible on Windows Vista computers. If you are using Windows Vista, please skip ahead to the end of this step for a briefly outlined alternative.]
This step will use the Microsoft Windows Performance Analyzer from the Windows Assessment and Deployment Kit (ADK) to identify the cause of any DPC latency spikes.

1. Download the ADK from this website: Download Windows Assessment and Deployment Kit (ADK) for Windows® 8.1 from Official Microsoft Download Centre
Ignore the reference to Windows 8.1. This download applies to both Windows 7 and Windows 8.

2. Run ADKSetup.exe and allow it to initialize past the splash screen.
[The following screenshots may be expanded by clicking on them if registered]

Click Next:
3.PNG


Click Next again (you may opt in to CEIP if you so wish - it is not necessary, but you may wish to do so):
4.PNG


Click Accept:
5.PNG


Alter the checkmarks to be next to the following box only:
Windows Performance Toolkit

and click Install.
10.PNG


Allow the install to complete:
11.PNG


and finally click Close:
9.PNG



Part 2:

[Windows 7] Click on the Start Orb, search for cmd, and press Enter.
[Windows 8] Swipe up or right click on the Start Screen, select All Apps, swipe or scroll to the right, and under the Windows System section, open Command Prompt.

Now, in Command Prompt:

Type out the following line and press Enter:
xperf -on DiagEasy

Nothing much will appear to happen, but xperf is now logging. Wait until the computer has gone through a period of stuttering slowness, and then type out the next line and press Enter (this line may take several seconds to process):
xperf -d %userprofile%\Desktop\trace.etl

Finally type this line and press Enter:
xperf %userprofile%\Desktop\trace.etl

If you get prompted the following message, select Yes:
1.PNG



A new window will now open, and after initializing, will containing several graphs.

Scroll down to the graph titled DPC CPU usage, right click on it, and select Summary Table. The example graph show below comes from a healthy computer, yours is likely to show much larger spikes and a smaller scale on the % usage axis.
2.PNG



A final new window will open containing a list of drivers. This list is already correctly sorted (by the Actual Duration column). The driver on the very top of the list is therefore likely to be the cause of your problem. Note down its name from the leftmost column.
3.PNG



You may now close both Windows Performance Analyzer windows and go back to the Command Prompt.

Type the following line final line and press Enter:
del %userprofile%\Desktop\trace.etl

Now close the Command Prompt window.


Part 3:

Now you need to fix the problem. With the driver name in hand, first try to identify where it comes from. Our Driver Reference Table (located here: Driver Reference Table) will help you with this task. It is a large database of many common drivers, and it is likely that the driver you are searching for is there. If you are, however, unable to identify the driver there, please do not hesitate to ask us for help.

Once you have identified the driver, you need to update it from the manufacturer's website. The Driver Reference Table should point you to such a website for the drivers that are contained within it.

Just download and install the latest version of the driver, and hopefully your DPC related problems will be resolved.


However, if they are not resolved, you continue to have problems after updating the driver, or you continue to experience other problems, please do not hesitate to ask us for assistance, providing as much detail as is possible. You will be required to register with this forum before you are able to create a new thread (you can register here: Register at Sysnative Forums), but this process is quick and completely free.



Alternative Step II for Windows Vista

As an alternative to Step II for Windows Vista computers, you may use a program called LatencyMon which can be downloaded here: Resplendence Software - Free Downloads

Once installed, start LatencyMon from the Start Orb > All Programs > LatencyMon.

In the top left hand corner of the window which opens, click on the green start button (highlighted in the image below). Then navigate to the Drivers tab, sort by the Total Execution (ms) column, and wait until the computer has gone through one of its periods of lagging or stuttering. Finally, read off and note down the driver at the top of the list, and continue with Part 3 of Step II.

4.PNG
 
Last edited:
Hi all,

According to LatencyMon something is wrong with my computer:

cGlujWP.png

What causes this spikes? If I sort the drivers by total execution (ms) on the drivers tab, then the first record is dxkrnl.sys with 0,203111 ms latency, which is absolutely acceptable I think (it's in the green section according to DPC).
Then what's the problem? And what causes these hard pagefaults and interrupts to process latency?

View attachment 18524

Thanks,
hazazs
 
And another with usbport.sys at the top of the list!

[SOLVED] Another high DPC latency issue with sound distortion

Hi, i have tried to do the above but when i enter the xperf command in cmd i have this message - nt kernel logger - access is denied. Please let me know what to do. I have had a high latency problem on my laptop and this causes a problem when i try to record music through an 8 track as i get constant dropouts. I gave up finding a solution and then came across this site so i really hope this works!! thanks for any help.

Nick

try running command prompt as adminstrator and follow the same instructions as before
 
And another with usbport.sys at the top of the list!

[SOLVED] Another high DPC latency issue with sound distortion

Hi, i have tried to do the above but when i enter the xperf command in cmd i have this message - nt kernel logger - access is denied. Please let me know what to do. I have had a high latency problem on my laptop and this causes a problem when i try to record music through an 8 track as i get constant dropouts. I gave up finding a solution and then came across this site so i really hope this works!! thanks for any help.

Nick

try running command prompt as adminstrator and follow the same instructions as before

do you realy think that this guy has still the problem after 3 years???
 
Hello, ive been suffering with small, tiny freezes, not systematically, but they occur, since i upgrade from Win7 to Win10. At least thats when i noticed it (it came to my occasion while i was watching a movie file).

Recently the term DPC came to my knowledge and i've been trying to understand what it is and try to analyse the results but im getting little progress.

Im posting a screenshot of the WPA, after 4-5minutes duration. Also, this is after i have removed Asus USB charge (orwhatsitsname).
dpc1.jpg
 
Hi Seitan. :welcome:

It is better if you open a new topic on windows 10 support (click) (not windows 10 tutorials), with a link to your trace.etl (to be downloaded by someone who wants to check it and trying to help you).
Did you use windows ADK for windows 10? Or 8-8.1? (it should be better to use the one for Win10)
 
Hi Seitan. :welcome:

It is better if you open a new topic on windows 10 support (click) (not windows 10 tutorials), with a link to your trace.etl (to be downloaded by someone who wants to check it and trying to help you).
Did you use windows ADK for windows 10? Or 8-8.1? (it should be better to use the one for Win10)

I used the one for Win10. The Sysnative's software disclaimer said that its not compatible with Win10, so even though i took it for a spin (everything was 4k+), i didnt pay much attention to it.
 
Hi there,

I've tried this step
Nothing much will appear to happen, but xperf is now logging. Wait until the computer has gone through a period of stuttering slowness, and then type out the next line and press Enter (this line may take several seconds to process):
xperf -d %userprofile%\Desktop\trace.etl

And I get this error:

"xperf: error: NT Kernel Logger: The instance name passed was not recognised as valid by a WMI data provider. (0x1069).

Any suggestions as to what I am doing wrong?
 
So I've run the test and here is my etl file

zQHevvB.png


Now... how exactly do I fix the problem?

Wdf01000.sys
ntoskrnl.exe
dxgkrnl.sys
 
Hey, I'm having trouble getting the xperf thing to work. This is what I'm seeing in the cmdPrompt.
C:\Windows\system32>xperf -on DiagEasy

C:\Windows\system32>xperf -d %userprofile%\Desktop\trace.etl
Merged Etl: C:\Users\Bente\Desktop\trace.etl
The trace you have just captured "C:\Users\Bente\Desktop\trace.etl" may contain personally identifiable information, including but not necessarily limited to paths to files accessed, paths to registry accessed and process names. Exact information depends on the events that were logged. Please be aware of this when sharing out this trace with other people.

C:\Windows\system32>xperf %userprofile%\Desktop\trace.etl
xperf: error: C:\Users\Bente\Desktop\trace.etl: The parameter is incorrect. (0x80070057).

Microsoft (R) Windows (R) Performance Analyzer Version 10.0.14393
Performance Analyzer Command Line
Copyright (c) 2015 Microsoft Corporation. All rights reserved.

Usage: xperf options ...

xperf -help start for logger start options
xperf -help providers for known tracing flags
xperf -help stackwalk for stack walking options
xperf -help stop for logger stop options
xperf -help merge for merge multiple trace files
xperf -help processing for trace processing options
xperf -help symbols for symbol decoding configuration
xperf -help query for query options
xperf -help mark for mark and mark-flush
xperf -help format for time and timespan formats on the command line
xperf -help profiles for profile options

C:\Windows\system32>
 
If you need help with the trace, open a new topic in the correct forum (if you have windows 8.1, open a new thread in the windows 8 forum).
Someone will check it.
 
OK,thank you for this favor
but I have a problem,this problem is when I tape the first command line (xperf -on DiagEasy) I meet this message in cmd (xperf: error: NT Kernel Logger: AccÞs refusÚ. (0x5).)
please anyone have idia ?
 

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