AdoredTV: Pascal DPC Latency investigated.

[h4rm0ny]

I hadn't paid a huge amount of attention to it but is this the problem Nvidia said they identified replicated, it was a driver bug and they would find a fix for it(though it took them some time)?

If so, saying it was never an issue seems.... stupid. This seems rather like those saying there was never a Kepler performance problem.... after Nvidia admitted the problem, promised a fix and released a kepler fix driver which significantly improved performance which had been lacking for the prior 6 months. Apparently it never happened despite Nvidia admitting it because if you test a post fix driver there is no evidence of lacking performance.

Personally, the AdoredTV guy was wrong on pretty much every single thing he said about Polaris... people keep linking to him and taking his videos seriously though. He puts in effort but he's consistently wrong which trumps how much effort or how convincing his videos are.

EDIT:- I went ahead and watched it, the guy is an idiot. He didn't actually have any noticeably latency problems, others are reporting a problem, having stuttering... it's being called a stuttering issue all over Nvidia forums. They then due to the stuttering find latency monitors to check if it shows anything. He never had the initial problem, saw a latency spike and finally realised there was a spike when alt-tabbing. But he never had any symptoms.

All the people complaining about stuttering which again Nvidia said they replicated, are not talking about alt-tabbing. This is my issue with him, he completely fundamentally mixed issues and comes up with stupid explanations. Other people don't have stutter because there is latency when alt-tabbing...

I don't think that's fair. He never says there isn't an issue, he says that he thinks a lot of people are thinking they have an issue when they hear about this "issue", go check, and then get false positives because they don't know what they're doing. Something I would think you of all people would agree with.

And he does end the video with a request to email him if they see anything wrong or do have problems this can't account for. Essentially the message is "I looked for this problem, couldn't find it, had a false alarm because of X and probably a lot of other people are making the same mistake'.

 

[shankly1985]

I can see why people would think they had an issue when tabbing out and it shows the problem.

Trust me if you have DPC latency issue you will know about it way before tabbing out a game.

 

[fs123]

he needed to actually find a way of finding the symptoms, ie, stuttering is the symptom, he used a card that had no symptoms and managed to diagnose that alt-tabbing, the sole intent of which is to interrupt full control that was handed to the game for fullscreen mode, causes a system interrupt, and then decided that if you don't play fullscreen, that system interrupt doesn't occur, and thus the DPC latency issue doesn't exist.

One, there are latency monitors that don't just show a max and current, but you know, a graph, which lets you see if there are multiple spikes or not and on which the alt tab spike would be painfully visible and most importantly, you need to have the symptom before attempting to find out what the problem is. If there is no problem with the card, looking for latency issues is a non starter and just frankly ridiculous.

This video is the equivalent of every idiot on a forum who says, "I didn't have a driver problem, therefore the drivers are fine", or the other type "I had a problem with drivers when I had card X, thus card X is awful and everyone who uses it must have the same problem". He basically said, he found the DPC latency issue and it wasn't a problem for him so it's probably not a problem for anyone else.

If Alt-tabbing is causing a latency problems then a way to avoid that is to use a dual monitor setup and view Latencymon constantly without tabbing. For reference I just tested Fallout 4 and Alt-tabbing does not give any latency spikes at all. Highest reported ISR and DPC were 199us and 269us respectively.


Referring to my previous post though, I forgot that another program I used to monitor latency was DPC Latency Checker. This did not give an indication of which driver may be causing a problem but was better to see latency spikes over time.

http://www.thesycon.de/deu/latency_check.shtml

Sadly it doesn't work with Windows 10 and doesn't appear to have been updated for a long time.

 

[Klo]

My DPC issues were caused by me not realising my motherboard sound was enabled when I have a dedicated sound card. Took a while to figure it out, but disabling the onboard fixed it immediately.

 

[drunkenmaster]

I can see why people would think they had an issue when tabbing out and it shows the problem.

Trust me if you have DPC latency issue you will know about it way before tabbing out a game.

Exactly, I can't recall exactly which system I had at the time, a good 4-5 years ago, the audio would keep just cutting out for a split second, giving a bit of static and it was irritating as hell. Forget what caused it in the end but I remember it was a latency issue caused by some driver.

The point being, people experience bad stutter, ask around about it, someone says check DPC latency via some tool and sure enough they can see a latency issue in real time as they get stutter in a game(or sometimes video, other things).

This whole thing is, lets check this problem free 1060, find anything that shows a latency hit and then exclaim maybe most people just have this.


As for alt-tabbing, it's really down to the game. I honestly again forget which but some games you hit alt tab and you're instantly at desktop and working, others go black screen for say up to 5 seconds and everything lags hard for a while then same going back into game, goes black screen and takes ages to 'load' back in. Depends on how the devs control holding onto resources I presume.

 

[Day187]

Alt n tab

 

[Rofflay]

As someone just about to buy a 1080 or TXP it concerned me there is a 67 page thread on this on the Nvidia forums. But consideting ive used latency tools for a long time and i am ocd about how clean my pc is then i can make some comments here. Firstly from what i saw it looks more like pre-rendered frames 3 than the 1 it should be causing the hitching i have saw in GTA V videos of the issue. If people set it to application controlled they deserve to have issues because that is pure lazyness.

Second is the alt tabbing and other things causing issues i always said alt+tab would change the feel of some games and people sniggered at me and said no. They also sniggered when i said my mic caused issues over usb which it did. Someone here has now also verfified how DPC can be weird and can happen for me just moving my mic to 6.3mmn to my soundcard takes me back to normal latency. But recently i also spotted that teamspeak instead of ventrilo makes me idle at 120 instead of 2-7us. Again Latencymon spotted this and i realized having the gui open and not minimized to system tray caused a consistant 120us instead of the minimzed 7us... Heck even removing things from a system will reduce it i recently chopped off some single digit idle numbers by simply using a new corsair keyboard that has no software running it is all saved internally on the flash memory of the keyboard my mouse is the same it is this kind of approach that would make me well placed to buy a Pascal and see if there is indeed issues.

I am making the move to Win 10 alongside my upgrade so i should know if it is Windows it could be the sheer amount of crap people have installed with Pascal for the LEDs or a bad upgrade to Win10 who knows the real issue i think is not Nvidia but people not taking care of thier computers then complaining. We have people in here who think 200us is normal sorry folks but a clean system should not be going over 55us load ever. The one exception is buffering the flash 4K Hobbit trailer on Youtube i will spike to 90 but once buffered im back to 55us. This is the number i get in demanding games too i alt tab just to see both run to get an idea because as someone else said DPCLatencytool has never been updated past Windows 7... Why is he using it? Use Latencymon and see if you can get 2-7us idle and 55us load. If not well look into it.


Oh and Nvidia hate HPET too but you will not be able to disable this without a custom bios now if it does indeed interfere with Win 10 they claimed it was gone but they said this in Win 8 too no and it takes me from 30us idle to 7. Latency is complicated to go after it you need a clean format first.