# DPC Latency Driver Issues



## hunterm12345 (Apr 1, 2012)

I'm sorry if this is in the wrong section, but I'm fairly certain this is the cause of a driver or drivers.

I've had latency issues recently with my sound popping/crackling and such, and I think these latency problems are actually starting to disturb my video game FPS too. 

I've noticed my cpu usage is around 10-20% when just browsing the internet, and I've also ran a DPC CPU Usage Summary using the Windows performance toolkit and extended the top 5 which you can see attached to this post. 

I'm not sure what I need to fix this issue according to this summary, and I was wondering if I can get any assistance. Thanks in advance.


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## satrow (Feb 4, 2012)

Hi Hunter,

This may be a problem better dealt with by the person most familiar with the computer in question 

Some useful tips (and a good software for Vista/W7) here: Resplendence Software - LatencyMon: real-time audio suitability checker

Also (the software works as far back as Win2K) here: DPC Latency Checker

Used in conjunction with the data you already have and your 'feel' and ears for how the PC responds to changes, there's a high chance you can get this problem fixed.

Any queries, attach further data for cross-reference and your hardware specifications and someone will try to help pin down the problem with you.


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## hunterm12345 (Apr 1, 2012)

I did forget to mention I've used both of those programs and that I've put together this computer myself. With DPC Latency Checker I keep getting a couple of red spikes in between my otherwise low green bars. I've attached the LatencyMon and Latency Checker results. I will also attach my DxDiag. I've searched through these things that are having the high execution countless times and I've yet to find any info that has helped, so I'm stuck. I also fiddled around with some of my BIOs setting but that seems to have done nothing. 

I fixed my FPS issues earlier so the audio crackling and popping is the only problem I have left. I need help, this issue is driving me crazy.

Edit: I forgot to mention that in LatencyMon the top few usually take turns in having a high execution or they all do it at once, I guess it just depends on the day. USBPORT.sys just all of a sudden spiked up to an insanely high number, which basically just proves my point. The problem drivers seem to range from ndis.sys, USBPORT.sys, nvlddmkm.sys, ataport.sys, and ntoskrnl.exe. Only ndis.sys seems to be a constant problem, USBPORT.sys is random and the others seem to also be random and rarely cause problems, but nvlddmkm.sys does tend to stay at a number pretty close to 1.


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## satrow (Feb 4, 2012)

I would expect *ndis* to be high on a computer with an internet connection actively used, similar with *USBPort* and USB chipsets/hardware, and *ataport* when any files are being read/written. Making a judgement on which of those might be 'too' high is a tough call. ntoskrnl - there would be no Windows without it, but if it's *very* high, it indicates that the kernel is working overtime, possibly because of a bad 3rd party driver.

If you've studied the troubleshooting techniques from the LatencyMon and DPClat websites, try reading this post for more clues: Monitor CPU & Ram over time - Windows 7 Forums


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