DPC Latency

[Aphelion]

First, if you haven't downloaded the DPC latency checker do it now, it's a great tool for checking system real time performance. While there, grab the PDF product sheet as well.

DPC Latency Checker

My Windows 7 machine is used mainly for audio recording and MIDI sequencing so I'm always looking for ways to optimize system performance. By "optimize" I'm not talking about getting every last bit of brute force power out of the system but instead, reducing the effect of the operating system and associated drivers on "real time" performance.

One of the best tools available is the above mentioned DPC Latency checker.

The last time I checked DPC latency I was getting a few spikes in the 600us range, still well within the green so I didn't pay it much mind. The past few days I'd been testing which "services" were unneeded for my use, I had moved several to manual start without any ill effects. Yesterday I just happened to check DPC latency....
Surprise!

The highest reading was 47us.

Here's a pic.



I hate to admit it, I wasn't keeping track of which services I switched to "manual start", DPC latency wasn't my concern so I didn't use my usual method of changing only one thing at a time. While I never had the unusually high spikes in the red, this shows that both services and drivers can affect DPC latency.

Ap

p.s. after this weekend I'll be running checks to find the "offending" :sarc: background service.

 

[Aphelion]

If you're getting interruption in audio streams, (pops, cracks, stuttering...etc) it is probably DPC latency, either that or hardware related IRQ or address space conflicts.

The program posted in message #1 can help give an indication where the problem lies, it's an open source free download. (I have no affiliation with DPC Latency Checker)

Ap

 

[whs]

Ap, if you are inclined and have the time, you may want to write a tutorial for the tutorial section. I bet a lot of people would appreciate that because it is one of those subjects that is probably not well known. And there are postings about audio problems quite frequently where a DPC latency check may help - especially with the additional info that the checker provides.

 

[Aphelion]

Ap, if you are inclined and have the time, you may want to write a tutorial for the tutorial section. I bet a lot of people would appreciate that because it is one of those subjects that is probably not well known. And there are postings about audio problems quite frequently where a DPC latency check may help - especially with the additional info that the checker provides.

I'd be glad to, I'm having a busy week but as soon as it slows down I'll start work on one.

Ap

 

[whs]

Ap, if you are inclined and have the time, you may want to write a tutorial for the tutorial section. I bet a lot of people would appreciate that because it is one of those subjects that is probably not well known. And there are postings about audio problems quite frequently where a DPC latency check may help - especially with the additional info that the checker provides.

I'd be glad to, I'm having a busy week but as soon as it slows down I'll start work on one.

Ap

Very good. I will be looking forward to it. If this is your first tutorial, ask Brink to give you a hand. He helped all of us and some things are not obvious when you use the tutorial section format.

 

[electrotune1200]

If you're getting interruption in audio streams, (pops, cracks, stuttering...etc) it is probably DPC latency, either that or hardware related IRQ or address space conflicts.

The program posted in message #1 can help give an indication where the problem lies, it's an open source free download. (I have no affiliation with DPC Latency Checker)

Ap

Thanks for the heads up on this. I'll have to give this a try.

It frustrates me till no end that something in Windows is not quite right with on-board audio. It's been this way since Vista with me, and I was really hoping
Windows 7 would get this right. I eventually just gave up and got a cheap external sound card which solved my audio complaints. It's just a shame that in some cases the only fix is buying an external unit for audio while otherwise, the rest of Windows 7 is just a dream.

 

[Aphelion]

<bump> Just to keep visible for a week or two.

Ap

 

[fireberd]

Good Post. As I use my PC as a "DAW" with Sonar (8.5.3) I'm always concerned with latency. My PC checks good with the DPC checker program and (fortunately) I'm not having any latency issues that affect my recording.

 

[Aphelion]

Good Post. As I use my PC as a "DAW" with Sonar (8.5.3) I'm always concerned with latency. My PC checks good with the DPC checker program and (fortunately) I'm not having any latency issues that affect my recording.

You're doing well then. Win-7 seems to be giving some folks a lot of grief, not sure if the drivers aren't up to speed yet or the motherboard BIOS setting need to be tweaked. (Not the user BIOS settings but the ones that are changed with a BIOS update).

There's a "Sonar" studio here in town, the owner/engineer/musician has used Sonar since it came out and gets a great sound. That's one of the programs.. along with Soundforge/CD Architect that completely follow the Windows/Microsoft programming guidelines.

Ap

 

[JazzSus]

There's a "Sonar" studio here in town, the owner/engineer/musician has used Sonar since it came out and gets a great sound. That's one of the programs.. along with Soundforge/CD Architect that completely follow the Windows/Microsoft programming guidelines.

Ap

Yes they follow MS guidelines because they are build on DirectSound architecture. I started with ProAudio9.3 and Soundforge6. Later on diserted to FLS and Cubase [ASIO architecture] and lately start learning Reaper and Bidul.

Without intention to hijack thread I have something related to latency in MIDI/Audio. That is if you load/import midi file to sequencer and you have SB installed on your computer than probably you dont have latency if you start replace instruments on different tracks with VSTi because SF2 is perfetly syncing. However if you dont have any SB installed and you have to use "Microsoft GS Wavetable Synth" [win build in soundmodule] Than later when you start replacing GM sounds with VSTi you run to sync problem. They sound way different-out of sync. You can try this just load midi tracks with SF2 and trigger metronom on. They will be synced. This doesnt happend when you use Win GM Wavetable. Midi and metronom are out of sync. Question is: Can this be fixed? I think it has nothing to do with DPC latency....or? TIA

 

[Aphelion]

Without intention to hijack thread I have something related to latency in MIDI/Audio. That is if you load/import midi file to sequencer and you have SB installed on your computer than probably you dont have latency if you start replace instruments on different tracks with VSTi because SF2 is perfetly syncing. However if you dont have any SB installed and you have to use "Microsoft GS Wavetable Synth" [win build in soundmodule] Than later when you start replacing GM sounds with VSTi you run to sync problem.

That's correct, the "Microsoft GS Wavetable Synth" is not a real-time device. That latency you're hearing is built into the MS Wavetable Synth and there's not anything you can do about it. Also, the MS Synth does not "report" it's built in latency to Cubase or any other program so it can't be compensated for.

DPC latency is different than latency used on audio systems. Latency in Audio/MIDI programs, Cubase, Reaper, Sonar...etc amount to nothing more than a buffer used to: 1. give the native DSP time to work, and 2. Sync both audio and MIDI streams.

If you go to the link in my first post and download the PDF support sheet there's a very good explanation of DPC latency.

Ap

 

[JazzSus]

Thank you for reply. Understand now.

 

[dynasonic]

Were you ever able to find what the #1 most offending program was in regards to your latency?

Thanks for this thread BTW. I can't wait to get home from work and try this program out!!!

 

[Aphelion]

Were you ever able to find what the #1 most offending program was in regards to your latency?

Thanks for this thread BTW. I can't wait to get home from work and try this program out!!!

It can be a driver (wireless, network adapter,...etc) and/or a process running in the background. It can also related to the BIOS, it's a good idea to update the BIOS to the latest revision.

Ap

 

[CommonTater]

I wish I'd kept the screen shots from this program... However I ran it on my HTPC machine under Win7 then again after re-installing XP (only present way to solve serious problems)...

Win7 == 300
WinXP == 37

Yes, that's right... 37.

Identical hardware, the same media player etc. That's almost a 10 to 1 ratio!

 

[Aphelion]

I wish I'd kept the screen shots from this program... However I ran it on my HTPC machine under Win7 then again after re-installing XP (only present way to solve serious problems)...

Win7 == 300
WinXP == 37

Yes, that's right... 37.

Identical hardware, the same media player etc. That's almost a 10 to 1 ratio!

37 ??

Yikes... that's low! No stuttering audio for you.

I finally have my Win-7 desktop down to about 106 at the highest, if I turn off the HPET (High Precision Event Timer) in the BIOS it goes down to about 47-50. That's as good as a Win7 machine is going to get.

Ap

 

[JazzSus]

Just did:
XPro SP3......Low> 7ms High Max> 64ms
Win7............Low> 101ms High Max> 210ms

Will try to tweak W7 whats running. Rushing to work, latter.

 

[CommonTater]

I wish I'd kept the screen shots from this program... However I ran it on my HTPC machine under Win7 then again after re-installing XP (only present way to solve serious problems)...

Win7 == 300
WinXP == 37

Yes, that's right... 37.

Identical hardware, the same media player etc. That's almost a 10 to 1 ratio!

37 ??

Yikes... that's low! No stuttering audio for you.

Hense my reason for switching... Win7 practically crippled my ASRock ION 330... and, sad to say ASRock is now shipping them with Windows 7 installed...

With XP installed that system will play a 1080p disk, stream AVIs over the network and defrag the hard disk all at once... With win7, it couldn't even play MP3s without stuttering and brapping at me.

I finally have my Win-7 desktop down to about 106 at the highest, if I turn off the HPET (High Precision Event Timer) in the BIOS it goes down to about 47-50. That's as good as a Win7 machine is going to get.
Ap

Given the really really bad media perfomance in ATOM based machines, yep, methinks they gotta work on that... rather a lot.

 

[CommonTater]

Just did:
XPro SP3......Low> 7ms High Max> 64ms
Win7............Low> 101ms High Max> 210ms

Will try to tweak W7 whats running. Rushing to work, latter.

Yep... that's pretty similar to my results. I think my max on XP was about 90 and the minimum about 15... going from memory.

 

[mike25907]

Frustrated

First, if you haven't downloaded the DPC latency checker do it now, it's a great tool for checking system real time performance. While there, grab the PDF product sheet as well.

DPC Latency Checker

My Windows 7 machine is used mainly for audio recording and MIDI sequencing so I'm always looking for ways to optimize system performance. By "optimize" I'm not talking about getting every last bit of brute force power out of the system but instead, reducing the effect of the operating system and associated drivers on "real time" performance.

One of the best tools available is the above mentioned DPC Latency checker.

The last time I checked DPC latency I was getting a few spikes in the 600us range, still well within the green so I didn't pay it much mind. The past few days I'd been testing which "services" were unneeded for my use, I had moved several to manual start without any ill effects. Yesterday I just happened to check DPC latency....
Surprise!

The highest reading was 47us.

Here's a pic.

View attachment 62957

I hate to admit it, I wasn't keeping track of which services I switched to "manual start", DPC latency wasn't my concern so I didn't use my usual method of changing only one thing at a time. While I never had the unusually high spikes in the red, this shows that both services and drivers can affect DPC latency.

Ap

p.s. after this weekend I'll be running checks to find the "offending" :sarc: background service.

Hi,
My name is Mike. I have been having a problem for a few months and can't seem to fix it. In short, I'm a mobile DJ who uses a PC. I have 2 laptops. One is a Dell with Windows XP and the other is a Sony Vaio with Windows 7 (64 bit). The software program that I'm using works perfectly with my Dell but freezes when I use the Sony. I've been on the phone with the software company and they had me do a million different things to tweak out the laptop. The last thing that they had me do was run a DPC latency checker. I've shut off basically everything and the results are always the same -
"Some device drivers on this machine behave bad and will probably cause drop outs in real time audio and/or video streams. To isolate the misbehaving driver, use default manager and disable/enable various devices one at a time. Try network and w-lan adapters, modems, internal sound devices, USB host controllers, etc."

I'm pretty good with computers, but I'm not way a pro. As far as shutting USB host controllers, I don't believe I did that. I'm not sure where to find them and which ones to shut. This is a copy of the thread form the software forum -

I've been having this same problem for a very long time.
I have 2 different laptops. One is a Dell with windows XP and the other is a Sony Vaio with Windows 7. The Dell NEVER gives me a problem, but whenever I use the Sony, Itch always ends up freezing up on me, whether it be 5 minutes into a set or 5 hours. The program freezes, but the track keeps playing. I am unable to use any of the controls on the VCI-300. I've done everything reccomended by both Vestax and the guys from Serato. I've purchased the Vestax power adapter, I analyzed all of my files and deleted all the corrupt ones and have done a million other things as well. Ever since I've deleted all of my corrupt files, Itch has been working fine for quite awhile, but last night while DJing at a BBQ using the Sony Vaio, Itch froze on me 4 times. I guess at this point, all that I want to know is - is Itch compatible with Windows 7??? I don't know what else to do. I'm also aware that a million other people are having the same problem with windows 7.
Someone PLEASE HELP..
Thanks




ITCH and the VCI-300 are completely Windows 7 compatible. What you are experiencing will be a conflict withing your Sony laptop.

So just to be clear you have done everything here: www.serato.com
And here: www.serato.com

Once you have the laptop setup for audio streaming, and if you are still having freezing can you please try the DPC Latency checker tool. This will show what is causing any remaining latency or IRQ conflicts on your system.
Go here: www.thesycon.de

Download then play audio form the software and run the DPC.exe.

You will be shown a bar graph , GREEN (SAFE) Yellow (Caution) Red (Dropouts).
You will also be given a report of any conflicting hardware or software.

Let me know what the report says.

Also can you please give me the laptop model, CPU, and list any other USB devices connected?

Cheers.
At 10:39 PM 31 May 2010
Matt-C wrote

Serato, Support




Hey Matt,
Thanks for getting back to me so quickly, I really appreciate it.

I have a Sony Vaio.
4.00 GB
Intel Core 2 Duo CPU
Windows 7
64 Bit

I've done everything that you said to do.
The last thing that I did was run the DPC Latency Checker Tool.
I clicked run, and went to sleep. When I woke up about 6 hours later, I went over to take a look. The results read -

"Some device drivers on this machine behave bad and will probably cause drop outs in real time audio and/or video streams. To isolate the misbehaving driver, use default manager and disable/enable various devices one at a time. Try network and w-lan adapters, modems, internal sound devices, USB host controllers, etc."

Now I don't know exactly what that means. Do I disable all of the above? Do I disable then enable the above? What does etc. refer to?





Disable them one at a time, then test to see if there are dropouts - this way you should be able to find out what is causing the interference.
At 2:03 AM 2 June 2010
Matt-C wrote

Serato, Support




Hey Matt,
I disabled -
my network adapters (Antheros AR9285 wireless network adapter and Marvell Yukon 88E8057 PCI-E Gigabit Ethernet Controler), my sound controllers and wi-fi and I'm still getting high yellow spikes every so often. I will let the DPC Latency checker run for a few hours and see if I get a red spike. I don't know what else to disable... This is very very frustrating to say the least.



OK Matt,
The DPC results are the same.. It says Some device drivers on this machine behave bad and will probably cause drop outs in real time audio and/or video streams. To isolate the misbehaving driver, use default manager and disable/enable various devices one at a time. Try network and w-lan adapters, modems, internal sound devices, USB host controllers, etc."


Sorry for the long post, I'm just hoping that someone can help.
Thanks so much in advance..

Mike