Lately I've been having a ton of issues involving DPC Latency. First, I will explain how I noticed this, and when it occurs.
The other day while running Media Player Classic x64, I noticed that whenever subtitles would display, my machine would act sluggish and the audio would be distorted. The video playback would also slow down and skip, too.
I was doing some research on the audio popping and distortion and that's how I learned about DPC Latency. I downloaded and installed LatencyMon and DPCLAT, and ran a few tests. In [this](http://i.imgur.com/QbHpuEp.jpg
) screenshot you can see the latency spikes when a subtitle occurs. I also noticed that when Steam (a game distribution and management program) is resized to a decent sized window, say 1600x900, or lower even that the latency also occurs. [This](http://i.imgur.com/ruHK1r7.jpg
) screenshot shows a continuation of the last without the subtitles and the latency while using Steam. Both of these tests are done with DPCLAT.
) you can see what LatencyMon shows, and if you scroll down you can see a text log of this test. My knowledge with computers is limited and I only know the basics, so I'm not entirely sure what to make of either of these. So some professional or experienced input would be greatly appreciated. This test was done while moving around the enlarged Steam window.
I have tried disabling devices to find the cause of this issue, but so far I've come up empty. Please not, that the yellow amount of latency has always existed on my system and I have never had an issue with it. It is caused by my Network Adapter, it is not directly supported under Windows 7 and the only driver that works with it creates quite a bit of latency. The adapter is a Linkysys WMP300Nv1.
You can see my other system specs [here](http://i.imgur.com/xiE13hm.jpg
) and [here](http://i.imgur.com/1SXx3w1.jpg
). If you need additional information, or want me to run additional tests, just ask. I would really like to solve this problem, as it has become incredibly inconvenient.
Another thing to note is that while playing games, everything is fine. I don't get any stutters or hindered gameplay.
I have also gone through almost every device on my system (that I can think of) through Device Manager and disabled them one by one while monitoring DPCLAT. I've disabled my Network Adapater (which solves the yellow amount of latency, but that's not the issue, I'm looking to solve the red spikes that are hindering my proformance,) my GPU, USBs, Keyboard, Mouse, etc. I have even tried a clean install on a spare drive and booted from that, but the issue persisted.
I also followed a tutorial on this website and according to that, USBPORT.sys, hal.dll, and dxgkernal are my top contenders for this issue. I don't know where to go from there, though. The tutorial I followed is here: https://www.sysnative.com/forums/wi...ues-with-wpa-windows-windows-vista-7-8-a.html
. So, thank you Niemiro for the tutorial, it at least helped me make progress.
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 or more DPC routines that belong to a driver running in your system appear to be executing for too long. Also one or more ISR routines that belong to a driver running in your system appear to be executing for too long. At least one detected problem appears to be network related. In case you are using a WLAN adapter, try disabling it to get better results. 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 0:00:49 (h:mm:ss) on all processors.
Computer name: BLANKITYBLANKBLANK
OS version: Windows 7 Service Pack 1, 6.1, build: 7601 (x64)
Hardware: MS-7388, MICRO-STAR INTERNATIONAL CO.,LTD
CPU: AuthenticAMD AMD Phenom(tm) 9750 Quad-Core Processor
Logical processors: 4
Processor groups: 1
RAM: 8191 MB total
Reported CPU speed: 2400.0 MHz
Measured CPU speed: 3369.0 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.
MEASURED INTERRUPT TO USER PROCESS LATENCIES
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): 12857.220680
Average measured interrupt to process latency (µs): 11.435882
Highest measured interrupt to DPC latency (µs): 4273.727527
Average measured interrupt to DPC latency (µs): 5.574959
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): 27304.758750
Driver with highest ISR routine execution time: hal.dll - Hardware Abstraction Layer DLL, Microsoft Corporation
Highest reported total ISR routine time (%): 1.732336
Driver with highest ISR total time: USBPORT.SYS - USB 1.1 & 2.0 Port Driver, Microsoft Corporation
Total time spent in ISRs (%) 3.551927
ISR count (execution time <250 µs): 79887
ISR count (execution time 250-500 µs): 0
ISR count (execution time 500-999 µs): 5
ISR count (execution time 1000-1999 µs): 5
ISR count (execution time 2000-3999 µs): 16
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): 27383.429583
Driver with highest DPC routine execution time: dxgkrnl.sys - DirectX Graphics Kernel, Microsoft Corporation
Highest reported total DPC routine time (%): 1.267533
Driver with highest DPC total execution time: dxgkrnl.sys - DirectX Graphics Kernel, Microsoft Corporation
Total time spent in DPCs (%) 2.622673
DPC count (execution time <250 µs): 251688
DPC count (execution time 250-500 µs): 0
DPC count (execution time 500-999 µs): 7
DPC count (execution time 1000-1999 µs): 3
DPC count (execution time 2000-3999 µs): 56
DPC count (execution time >=4000 µs): 0
REPORTED HARD PAGEFAULTS
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: msmpeng.exe
Total number of hard pagefaults 32
Hard pagefault count of hardest hit process: 29
Highest hard pagefault resolution time (µs): 19637.313750
Total time spent in hard pagefaults (%): 0.031834
Number of processes hit: 4
PER CPU DATA
CPU 0 Interrupt cycle time (s): 4.102835
CPU 0 ISR highest execution time (µs): 27304.758750
CPU 0 ISR total execution time (s): 2.929069
CPU 0 ISR count: 50344
CPU 0 DPC highest execution time (µs): 4299.791667
CPU 0 DPC total execution time (s): 0.767351
CPU 0 DPC count: 138502
CPU 1 Interrupt cycle time (s): 1.127016
CPU 1 ISR highest execution time (µs): 26713.672083
CPU 1 ISR total execution time (s): 0.715634
CPU 1 ISR count: 289
CPU 1 DPC highest execution time (µs): 144.894583
CPU 1 DPC total execution time (s): 0.019271
CPU 1 DPC count: 1118
CPU 2 Interrupt cycle time (s): 3.879640
CPU 2 ISR highest execution time (µs): 27263.870
CPU 2 ISR total execution time (s): 3.096896
CPU 2 ISR count: 1712
CPU 2 DPC highest execution time (µs): 27383.429583
CPU 2 DPC total execution time (s): 0.545554
CPU 2 DPC count: 5847
CPU 3 Interrupt cycle time (s): 5.664164
CPU 3 ISR highest execution time (µs): 20403.102083
CPU 3 ISR total execution time (s): 0.226855
CPU 3 ISR count: 27986
CPU 3 DPC highest execution time (µs): 27381.437917
CPU 3 DPC total execution time (s): 3.813194
CPU 3 DPC count: 106440