DPC Latency Checker

[Ao1]

I just came across an interesting monitoring tool. Simple and free for non commercial use. Probably not much use for storage but interesting anyway.

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

Thesycon’s DPC Latency Checker is a Windows tool that analyses the capabilities of a computer system to handle real-time data streams properly. It may help to find the cause for interruptions in real-time audio and video streams, also known as drop-outs. The program supports Windows 2000, Windows XP, Windows XP x64, Windows Server 2003, Windows Server 2003 x64, Windows Vista, Windows Vista x64, Windows 7, Windows 7 x64.

If any kernel-mode device driver in your Windows system is implemented improperly and causes excessive latencies of Deferred Procedure Calls (DPCs) then probably drop-outs will occur when you use real-time audio or video streaming applications. For an explanation of this effect see Background information below.

The DPC Latency Checker tool determines the maximum DPC latency that occurs on your Windows system and thus enables you to check the real-time capabilities of your computer. DPC Latency Checker works independent of any external hardware. Using this tool may be helpful in the following situations:
You experience interruptions (drop-outs) in a flow of data processed in real-time, for example an audio stream, video stream or a sequence of measuring data, and you want to find out the reason for this problem.You want to verify that your Windows system is configured properly so that it is capable of handling real-time data transfer before you install the corresponding streaming application.You want to check if a particular computer system is suitable for streaming applications, for example before you buy this system.

[One_Hertz]

That is so cool haha. What are people seeing for latencies when just idling with a few apps? Here is mine:

[Ao1]

Mine sucks in comparison

[One_Hertz]

Mine sucks in comparison

Something is wrong with your rig... This latency doesn't seem to depend on the speed of anything. I checked with a friend who has a pretty slow PC (3ghz c2d, raptors, 4870) running windows 7 and he had ~20us latency.

[Computurd]

yeah the latency doesnt seem to change for me no matter what i do, such as run multiple programs/av scanner. wondering if this tool is any good? nice find though ifn it works.

[One_Hertz]

yeah the latency doesnt seem to change for me no matter what i do, such as run multiple programs/av scanner. wondering if this tool is any good? nice find though ifn it works.

Mine changes... If I launch some heavy game like dragon age it jumps to 400 momentarily. Also, if I launch a bunch of apps the average jumps to 40ish.

[Ao1]

Intriguing. I don't know if your latency is just insanely low or if mine is retardedly high, but I'm on a mission now to get mine down.

AFAIK DPC latency has nothing to do with the speed of the pc it is to do with latency between the cpu and the rest of the system at driver level.

If I run in safe mode my system is a lot more snappy so there must be a driver or back ground service slowing things down somewhere. The difference between safe mode and normal mode is like the difference between ssd and hdd.

EDIT:

Abbreviated from here: http://www.raymond.cc/forum/tutorial...y-checker.html

DPC Latency Checker measures the response time of your system. The response time is influenced by any other application that is currently running on your system. For an accurate result, we recommend you to close all applications before launching DPC Latency Checker. If you run this tool while there are applications open you will notice that, while you close them, the results will improve.

Device drivers are high-priority tasks that need to be processed right away before any other task. If a device has an improper driver this operation is going to take more time than usual and it's going to slow down the system.

The length of delay varies greatly between computers and the software and device drivers installed on them. DPC Latency Checker is a tool for checking how bad the latency of a computer is, and can then be used for troubleshooting.

The checker can be left running while changes are made to the computer to see if they improve the situation

Unfortunately DPC Latency Checker only shows if there is a device driver problem, not which driver is causing the problem. You will have to manually disable and then re-enable each device driver from Device Manager.

EDIT:

@One _Hertz, was your pc switched on when you ran that check

Disabling drivers one at a time could not find my problem. Maybe it's a back ground service or maybe it's just an accumulation of lots of things.

[Musho]

Mine sucks in comparison

My latency graph is similar to yours. This rig has never been really smooth in gaming. But then again, I'm running an Asus board. I plan on going i7 with a gigabyte board in the near future. This is on a fresh install btw.

[Musho]

yeah the latency doesnt seem to change for me no matter what i do, such as run multiple programs/av scanner. wondering if this tool is any good? nice find though ifn it works.

What kind of latency are you getting?

[Musho]

It seems like the latency checker agrees my games aren't running smoothly. This was with a single HD5870 running BF:BC2. Even if I have a solid 60FPS, it can still feel choppy (a bit like how people describe microstutter, although I am running a single GPU.). It's done this on multiple windows installs, with different videocards, different PSUs. Only thing that hasn't been different, was the RAM, motherboard and CPU. I doubt a Q9650 can cause this problem, nor can the ram. I think I'm looking at a crappy mobo here. Makes me look even more forward to upgrading.

Edit: Will ask people in the Maximus II Formula thread to run this program. Also, audienceofone, what mobo are you running?

[One_Hertz]

if I plug in a keyboard with a semi failed USB controller the latencies jump to 5k every few seconds

Looks like it at least somewhat works.

[Gogeta]

OneHertz, I think we'd all love to know how your results are so low! What OS are you running?

Here is mine:

Xeon 3110@4.1, 4GB DDR2-1211, DFI P45-T2RS, 4870 1GB, X25-M G2, Win7 x64

[Ao1]

Edit: Will ask people in the Maximus II Formula thread to run this program. Also, audienceofone, what mobo are you running?

Asus Rampage Extreme. ICH9, Intel G2, 4870x2 & 6gb ram.

I've tried disabling drivers, disabling features in the BIOS and disabling services. No change. It must be @ OS level however because things get snappier in safe mode. Unfortunately DPC Latency Checker does not work in safe mode. I think it acts as a driver so safe mode is a no go.

@ One_Hertz are you still using a stripped down version of XP? Maybe this is just Win 7?

[One_Hertz]

@ One_Hertz are you still using a stripped down version of XP? Maybe this is just Win 7?

Yes I am running a very light xp x64 with everything I do not need disabled, but that is not why my results are low. My friend is running a full version of windows 7 ultimate and he sees 15-20us. There is nothing in common between our rigs at all.

If I move the mouse back and forth very fast it goes from 14 to 25. My windows xp laptop (full version of XP though) is showing results like yours... 85ish.

[Musho]

OneHertz, I think we'd all love to know how your results are so low! What OS are you running?

Here is mine:

Xeon 3110@4.1, 4GB DDR2-1211, DFI P45-T2RS, 4870 1GB, X25-M G2, Win7 x64

All people so far with 100ish latencies are running Asus boards. Are you, by any chance, running an Asus board as well?

[Musho]

Yes I am running a very light xp x64 with everything I do not need disabled, but that is not why my results are low. My friend is running a full version of windows 7 ultimate and he sees 15-20us. There is nothing in common between our rigs at all.

If I move the mouse back and forth very fast it goes from 14 to 25. My windows xp laptop (full version of XP though) is showing results like yours... 85ish.

What board are you running?

[One_Hertz]

What board are you running?

gigabyte EP45-DQ6

[Musho]

yeah the latency doesnt seem to change for me no matter what i do, such as run multiple programs/av scanner. wondering if this tool is any good? nice find though ifn it works.

What latency are you getting, and what motherboard are you using?

[Musho]

gigabyte EP45-DQ6

This is interesting. So we have you running a gigabyte board with sub 20 latencies, while audienceofone and me are using Asus boards and getting 100+ latencies. I wonder if there's a correlation between the motherboards used and the latency. We need a far bigger sample size for that, though.

People, please run this tool and report your latencies + the motherboard you are using. If you have the time, please include other information like OS used, and other components as well, please. Thanks!

[zalbard]

EVGA x58 Classified, Samsung F3, Auzentech Forte, 5870, Win7 x64. The latency is jumping around a lot... Usually around 70-150us, but sometimes jumps to 500-1000us! :o
I am not experiencing any issues, though. I tried changing the mouse and it made no difference whatsoever. I think it's the audio card, it's buggy sometimes. Oh, and I need a reinstall, but doubt it's the case.

[Musho]

EVGA x58 Classified, Samsung F3, Auzentech Forte, 5870, Win7 x64. The latency is jumping around a lot... Usually around 70-150us, but sometimes jumps to 500-1000us! :o
I am not experiencing any issues, though. I tried changing the mouse and it made no difference whatsoever. I think it's the audio card, it's buggy sometimes. Oh, and I need a reinstall, but doubt it's the case.

Thanks for your contribution! This was at an idle desktop, correct?

[zalbard]

Yeah.
Tried disabling the sound card, the mouse, the gamepad (although not sure I disabled it entirely) the RAMdisk, the DVD drive, the network adapter, all the ATA controllers, most USB controllers, didn't help. Couldn't disable the keyboard properly (can only uninstall the driver it seems... Razer Lycosa).

[Musho]

Hmmm, another thing has just struck me. Of the people having 100+ latencies, we're all using ATI cards. I'm using a 5870, Zalbard is as well and audienceofone is using a 4870x2. What videocard are you using One_Hertz?

[Musho]

Something is wrong with your rig... This latency doesn't seem to depend on the speed of anything. I checked with a friend who has a pretty slow PC (3ghz c2d, raptors, 4870) running windows 7 and he had ~20us latency.

Nevermind for the videocard comment. This guy with a 4870 seems to run with low latencies just fine. That leads us right back to the motherboards again

Edit: One_Hertz, do you happen to know what mobo that friend of yours is using? Thanks!

[zalbard]

I've tried disabling pretty much everything, no clue what's the issue...