I have serious DPC Latency problems :(


New Member
Ok here is what I posted to Gigabyte to see if they have a solution, I thought I'd post here too. Maybe one of you can help me out.

I am having some DPC Latency issues with Windows 7 64 bit.

I am having a really hard time trying to solve the problem, I have went into device manager to disable device drivers to see if the DPC Latency would stop spiking but nothing seems to be working.

I downloaded the DPC Latency program because I was noticing that I was getting very short CPU lags from time to time, and also audio crackling/lag. So I looked into this program and it was showing the graph spike yellow and red when I run programs, It seems to be totally random.

The weird thing is, is when I am playing a game that requires a lot of CPU, and I alt+tab to see what the graph is doing, the graph is all green with very low latency.

But once I get back to the desktop, that's when it starts to spike again. So during high-demanding games the graph will be all green.

I have all the current drives and the newest BIOS update. I have formated my PC several times to see if it would fix the problem, but it's the same problem every time with Windows 7.

The problem seems to be totally random, sometimes it will spike when I load programs (any program) and sometimes it will not.

It seems like it is causing the CPU to micro-stutter, and affects music sometimes because it will crackle. I have tried onboard sound and a high-end sound card, still the same thing happens.

Is there anything I can do?

NOTE: I just installed the Energy Saver program from the Gigabyte website to see if it would cause any problem. Well I turned the program on an looked at the DPC display and it's all red bars. I then turned on an mp3 to see if it would cuase any skipping/crackling and it is really bad.

With Energy Saver turned on the DPC displays every bar red at different heights and audio will stutter badly.

Here is a picture:

Image - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting

Sorry that this picture isn't saved on your servers, I had to modify this so I can add more info in.

Model Name : GA-EP45-UD3L(rev. 1.0)
M/B Rev : 1.0
BIOS Ver : F9
Purchase Dealer : NCIX.com
VGA Brand : Nvidia Model : Palit 8800GT
CPU Brand : Intel Model : Quad 6600 Speed : 2.40
Operation System : Win 7 64-bit SP :
Memory Brand : G.SKILL Type : DDRII
Memory Size : 4 Gigs Speed : 1066 (PC2-8500)
Power Supply : 650 W


New Member
I think nobody commented because they have no idea what the problem is :(.

creo que tenia el mismo problema

hola! te cuento que tengo el mismo mother,gigabyte ep45-ud3l y tenia el bios f1,se me dio por actualizar a la ultima version f9 y empece a tener problemas,la pc se congelaba cuando jugaba o miraba videos online,asi que volvi a poner la version f1 del bios y chau problemas,espero te sea de ayuda


New Member
Me no speak that language :).

I have this same issue! We have pretty close system specifications. I am wondering if our motherboards are bad.

I tried everything -- and one thing I noticed is that running Prime95 x64 on all cores eliminates the high spikes in DPC latency checker 1.2.0. Audio stutter, which original got me searching for fixes, led me to DPC latency checker.

It really is strange that 100% CPU utilization would cause the DPC latency to stabilize (mine hovers around 350-450 microseconds during full CPU utilization, but in idle or moderate usage settings seemingly anything causes a DPC spike).

Let me know if you figured it out!

Model Name : GA-EP45-UD3P(rev. 1.6)
M/B Rev : 1.6
Purchase Dealer : Newegg.com
VGA Brand : ATI Model : 5770
CPU Brand : Intel Model : Quad 9400 Speed : 2.66
Operation System : Win 7 64-bit SP :
Memory Brand : G.SKILL Type : DDRII
Memory Size : 4 Gigs Speed : 800
Power Supply : 550 W Antec Neopower

Wow, this is starting to get really common and especially for 64 bit.
I basically blame the drivers not being done yet; I have been having the issue for some time now, and I really am not sure what triggers it. I think that Realtek is part of the reason. because these guys cannot seem to write good audio drivers ever. heck even the pre windows 7 (vista) drivers cause less DCP latency than the newer ones. I also could blame this partly on MS not tidying up their x64 OS, I mean these issues have been more frequent in x64 than x86 at least since XP.
But now that more and more people are switching over, maybe we will see better drivers soon, I also think I have a problem with my ati graphics drivers; as whenever i watch movies in VLC using the default (Direct3D) rendering my DCP latency spikes like crazy. But switching it to OpenGL there is no such problem.

I also believe that most people don't know too much about this DPC stuff anyway. and I am yet to find out someone that can verify that it is in fact hardware issues or driver issues that cause high DPC levels. And when are DCP levels to be measured? I mean when I have restarted my system i can go for at least 5 hours without a single spike. I am pretty sure that programs like uTorrent are boosting these DCP spikes to show up as well. And Windows really has issues with handling too many connections at the same time. I used to experience system lag in XP and Vista 64 when being in uTorrent too long. But it used to be enough to kill uTorrent and start it over.
This doesn't work for me in 7 for some odd reason.

Despite the fact that I still have DCP spikes I notice them less now than I did before. I think that is partly that I have disabled the Pagefile to be written by Windows. as I believe that it goes without saying that no matter how fast your HD or your CPU is, they will spike every time windows is trying to dump 12 GB+ of data onto your harddrive on a regular basis. I mean its kind of odd that the pagefile is still ONE file, it should have been a folder with smaller parts so that the system doesn't have to update such a huge file every time.
This topic really is a big one for me, because I want to reach system stability, but without 32 bit drivers being discontinued and full focus on 64 bit drivers is a reality I doubt that our DCP latency will be 100% stable.

I got decent <300us average DPC times, finally, after disabled IEST (Intel Enhanced Speedstep, I think) in my BIOS.

This was after a few hours of disabling everything, but after that one change everything is back to the way it was. Well, I did update my BIOS, but that didn't fix the problem in itself.

I attached some graphs that show how IEST was the suspected cause of my problems --- high CPU usage prevents the underclocking/switching of speed, so it made sense to disable IEST completely.

Note I was able to turn back on C1E/C2E/C4E/C6E (all the CxE options). So I do appear to have some speedstepping - but it's not causing those crazy DPC spikes and audio stutters.

To help other searchers, a summary:

Gigabyte UD3P / Intel P45 / Windows 7 x64
Problem: DPC random, spiking
Solution: DPC made acceptable, below 500us almost all the time, by disabling IEST in BIOS


Yes, that is absolutely right. Turning off the speedstepping thingy is definitely worth doing if you want your system to be stable, and is also a must if you have OCed your system.
I wouldn't say that my DCP levels have ever been that crazy though. at least not as for late. and in my case my CPU commonly stays below 65us, but every once in a while its going to mess up with a spike here and there.
but I suggest you let your system run for at least 5 hours before checking your DCP latency. and also run all kinds of apps you commonly do; For me, my computer must be running several hours actually processing before DCP latencies starts to pop.

Also try terminating the micorsoft malware protection process. Stick to your other scanners and firewalls. The process is called mpcmdrun. It seems they have not yet perfected windows defender and it indeed freezes the system.

BLESS YOU. You are my hero. Thank you so much from the bottom of my heart. Stuff of legends tier advice. My problems are solved. I love you. Seriously. I hope goodness rains down on you and you find everything you want in this life.


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