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A call to ALL Nvidia owners - It's time to check our latency

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Annisman*

Golden Member
Aug 20, 2010
1,844
70
91
I don't think so, I think that audio playback is often times where dpc latency is most clearly noticed but that's not primarily where it comes from.
 

brandonmatic

Member
Jul 13, 2013
199
21
81
I just tried this myself and I get huge latency spikes and I'm running a R9 290x. Are you sure this is an Nvidia problem? Seems like it could be any number of things.
Edit: The latency is caused by ataport.sys.
 
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littleg

Senior member
Jul 9, 2015
355
38
91
720M on my laptop shows some spikes. Only ran a game for a couple of minutes and the interrupt to process latecy went up to 1523. DPC went to 655 and the bottom one (pagefaults) hit a ridiculous looking 575879.
 

Annisman*

Golden Member
Aug 20, 2010
1,844
70
91
Ignore the page faults those are normal. Dpc latency can be caused by anything, what we are looking for is when it says Nvidia kernel driver is the offender. If you get latency from something else you should look into updating drivers for whatever is causing it.
 

littleg

Senior member
Jul 9, 2015
355
38
91
It was the nv driver when I posted that, it's gone up now and changed to the Microsoft NDIS. Highest execution on the NV driver was that 655 and that was when I had a game running.
 

Madpacket

Platinum Member
Nov 15, 2005
2,068
326
126
While I await for the 1060 to arrive I went ahead and ran Latencymon on my Steam Box. It has an 860M (Geforce 750 Ti).

No DPC issues with nvddm using the latest drivers (no hotfix).
 

Deders

Platinum Member
Oct 14, 2012
2,401
1
91
I'd like to point out that there is a difference between what musicians refer to as audio latency and DPC latency, even though high DPC latency can cause similar results to what happens if your soundcard isn't set up properly for audio programs.

Audio latency in music programs usually refers to how well your sound card handles the audio, and if you need to increase the latency from the program to the soundcard in order for the buffers to be able to retain enough data to avoid stutters.

DPC latency is more system wide, but if for instance there was an added delay related to DPC latency when talking to the soundcard driver, then you might have to increase the audio latency to compensate, in effect delaying what you hear further away from when the sounds are triggered in order to make sure all the hardware/software involved can keep up.

I'd also like to repost what I said in the other thread as there are other factors that can cause DPC latency, and it would be easy to get them confused.

How many of the people who have seen this are still using the upgraded version of windows 10 as opposed to a fresh install? The upgrade will use older drivers (designed for win 7 or whatever) in compatibility mode which induces latency much like the results seen on screenshots.

Another time I've seen high latencies like this is due to a bug in the intel.inf motherboard drivers installer on x64 bit systems not actually installing all the necessary drivers. The same installer package will install drivers properly on x32 systems, but leaves loads out with x64 which does lead to timing instabilities, highe latencies and less performance which can affect the WEI score.

Installing the package with the -overall switch usually results in better performance and latencies.

I'm not saying that there isn't a problem with the Nvidia drivers, but it would be much easier to isolate if these other issues were ruled out of the equation.
I did see the Nvidia driver spiking with my 780 before I did the fresh install of windows 10, but this didn't really noticeably affect benchmarks or game performance for me.

I would say that the measurements we are seeing are only the surface so unless you are a high level engineer or you write the drivers, it will be very difficult to pin down exactly what part of the hardware or code is causing the spikes.

My 1080 arrived the day after the beta drivers were released and they are the only drivers I've ever used for this card. DPC latency has been fine for me.
 

Golgatha

Lifer
Jul 18, 2003
11,926
181
106
Tested a GTX 1080, GTX 1070, GTX 980 Ti, and a GT 520 just for kicks and giggles. All passed with flying colors, but the 1080 and 1070 had to have the hotfix 386.95 drivers to get rid of intermittent spiking.
 

nitromullet

Diamond Member
Jan 7, 2004
9,031
36
91
I finally got the chance to test the hotfix with Ableton Live, and I am pleased to say that the issues appear to have been fixed. My Windows machine is usable as a DAW again.

Hopefully this will stay on NVIDIA's radar and gets implemented in subsequent drivers for past architectures as well.
 

mojothehut

Senior member
Feb 26, 2012
354
6
81
Here's my 980ti on the most recent drivers.
Should I be worried about that bottom bar? Such redness :thumbsdown:





Rig:
Asus Maximus Hero Z87
Intel 4770k @ 4.5ghz
16gb DDR3 1600
Win10 Pro
EVGA 980ti Classified (1500mhz core)
 

Deders

Platinum Member
Oct 14, 2012
2,401
1
91
No, the bottom bar is for hard page faults. I expect most people get these.

Basically if windows can't find something it needs in the memory or the page file, it looks for it on your hard drive and the red bar is how long it takes to find it.

I would have thought that if a file was needed in memory after it had been loaded, it would be there. Apparently this isn't the case.
 

amenx

Platinum Member
Dec 17, 2004
2,783
539
126
Have a feeling the incidence of this occurring on non-Pascal Nv cards may not be any more prevalent than may occur in rigs with AMD cards. With Pascal it was Nvida driver related. But too many variables, incl drivers for mobo components, addon sound cards, NICs or other things can contribute to DPC latency issues.

http://maxedtech.com/the-case-of-dpc-latency/
 
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Annisman*

Golden Member
Aug 20, 2010
1,844
70
91
Anybody dealing with any kind of latency should look to make sure HPET is disabled in bios, it's not needed for W7+ and can cause issues.
 

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