Choppy Sound, Video and DPC Latency Issues

Hello everyone, I'm the owner of an Acer Aspire 8735G which runs Windows 7 64-bit. Its a great laptop but I'm having major headaches with the playback of audio and video files on random occasions. This, I am almost certain, is due to a really bad DPC Latency.

Whether running music in iTunes, or videos in any application be it players or browsers, the laptop seems to struggle to play the media back smoothly. There is a lot of choppiness with the audio and video. I've checked the task manager to rule out CPU spikes and I've downloaded all the up to date Realtek and Nvidia drivers to try and rule driver issues out and still no luck.

After downloading DPC Latency Checker though after a google search, I soon realised it was a problem with DPC Latency. Some of the red bars in the program are so high that they go off the screen. There doesn't seem to be a pattern to it though, one minute the bars are all green and below 500 and then they are shooting up to 2000 and beyond. I actually have a couple of screenshots on my desktop, but I'm not exactly sure how to get them on here haha! The program suggests to disable drivers one by one in the device manager but asides from disabling and eventually re-enabling the wireless and sound drivers, I'm not sure what else I can test with without causing more problems.

I've been all over the net in recent weeks trying to find the answers to the problem and every forum seems to have a different idea. So I've come here looking for help, its normally a great forum. Some places I've looked at are suggesting BIOS updates and even failing hard drives... I know the hard drive to be fine for certain because it was recently replaced for a larger one and the problem was there both before and after (this also included a clean install of Windows 7 and drivers from Acer's website).

Thanks in advance, and I've also put a link below to some playback that I've actually recorded through my camera from the screen. All the distortion that you can see in the video and audio is exactly as it was recorded and what I want rid of... its nothing to do with the camera itself or youtube. As you will see, it starts off very choppy and then suddenly recovers and plays the remaining seconds with no issues.. its just weird and happens so randomly!

Choppy Video and Sound - YouTube

 

bumped.. sorry about that, I'm really struggling to find any answers to this. Thanks!

 

Some Acer laptops use Chipset Clock Modulation which can instantly slow your CPU down to a crawl and you can see much higher DPC Latency when this happens. A bit of a long shot but try downloading ThrottleStop and check the Log File option and make sure both types of Clock Modulation are always reporting 100.0%.

You can upload a screen shot to ImageShack® - Online Photo and Video Hosting and then post a link here of the forum thumbnail. Show DPC Latency when the bars are going off scale into the red and include ThrottleStop in your screen shot. There might be a clue in the TS data.

 

Thanks a lot for that! I've downloaded Throttlestop and both types of Clock Modulation are at 100% constantly, so it looks to be OK there.

As for the images, that's appreciated too! I've uploaded two random screenshots from DPC Latency the other night and a screenshot of the monitoring screen of Throttlestop that I took just now. They're posted below. Its clearly an intermittent issue, I've turned DPC Latency on today again and the bars are red only once every few minutes, with video files playing MOSTLY with no problems. Something somewhere isn't agreeing with the sound or CPU though, I just really want to know what it is!!! haha

Thanks again!

ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting

And I'm also sat with it now trying to catch a few red bars that go off the scale so I can post that, it might be difficult tonight though. Its typical once I come on these forums that I can't get a screenshot when I need it! lol

And here's the red bar going off the scale (just to show I'm not going mad!) haha

ImageShack® - Online Photo and Video Hosting

 

About all you can do to track this down is to go into the Device Manager and start disabling drivers one by one until you find out the one that is causing the problem. Sound and wireless network cards are two of the biggest problems.

If you can find the one causing your DPC latency issues, you might be able to find an earlier driver that doesn't have this problem. The newest driver is not always the best driver. Hopefully another 8735G owner will run the DPC Latency tool to show what's normal for this laptop.

Edit: The Realtek wireless driver is the biggest DPC latency problem on my desktop computer. Disable that in the Task Manager and see if things clean up significantly.

 

Thankyou, I may have a breakthrough. Whenever disabling the NVIDIA GeForce GT 240M display adapter, the DPC Latency seems to be more stable. And whenever re-enabling, the latency goes through the roof again. Disabling any other drivers doesn't seem to have the same effect, and I've been through a lot of them now.



Uploaded with ImageShack.us

The point where I re-enable the display driver is at -25 so you can see that seems to cause a lot of the problems.

 

If you ever find a Nvidia driver that doesn't cause severe latency issues then post the version number. Shocking how one poorly programmed driver can screw up an otherwise good computer.

 

It looks like your not wrong, I guess I'll just have to start the long process of going through them all, but if and when I do find the missing link I'll be sure to post back here! Thanks!

 

OHHH NOOO. this thread kinda just broke my heart. Ok i run music production software (ableton) on this same exact laptop. I have been pulling my hair out for the last 2 months, over major cpu spikes rendering my software pretty well useless. I found it was the video card through the same method.

did anybody ever find a working driver for this card? Or am i stuck with a 1000$ piece of garbage.

 

Try this out, go to Device Manager and under Batteries disable Microsoft ACPI-Compliant Control Method Battery and then check your DPC's.

 

Thanks for the replies again... I've got to say that unfortunately (and unbelievably!) I'm still having these issues! I'm not wanting to accept defeat with this but with the amount of uni work I have on i'm struggling to find the time to really fix this (without bricking my computer trying haha).

In reply to Deep Dose its at least reassuring that I'm not alone in this, in that at least we both know our laptops aren't broke in some way!! I feel your frustration though! This is meant to be a high spec laptop, but this one at the minute struggles to do anything! I still haven't found an Nvidia driver that agrees with this thing. As a bit more help, I suggest you try downloading a program called latencymon.. its like dpclat but better because it shows you which drivers are actually causing the problems! If you could let me know what your problem drivers are that would be a huge help!

And to ttomorad, its interesting you say that! I actually tried that about a month back! One of the problem drivers with me is ACPI.sys at something ridiculous like 3.2 ms on latencymon!! I disabled the ACPI-Compliant Control Method Battery and it did help!.. but it isn't the only driver causing fault. Obviously the nvidia driver nvlddmkm.sys had an execution of 1.4 ms, ndis.sys was at 2.2 ms and something called ataport.sys was also at 1.4.

This meant that although it helped, it wasn't enough and it was more trouble than it was worth turning it off.. whenever I forgot to plug my laptop back in it just shut off without warning because I didn't know the battery level haha!!

So (very) long story short I just don't know where to go anymore! There's too many drivers causing problems and since the time of the first post i've had the hard drive changed and obviously a fresh Windows install, proving that its not a dodgy install. I'm clueless, any help is great!

 

I had major problems with my DPC spikes on my 7720G and I did a lot of research about this. Today I still have high DPC's but not as frequent as before, the biggest improvement was after BIOS update and latest chipset drivers. Also, disabling Wi-Fi card in Device Manager shows a very big difference, some users said that disabling your CD/DVD drive also has major effect, I didn't see any in my case. Try disabling everything you can in Device Manager and see what happens; Bluetooth, Wi-Fi, FireWire, webcam, anything you can find, but get the latest chipset drivers!

 

Hi again, right I've practically finished uni now and my next big thing is getting this laptop working properly without spending any money on it!! So I just thought I'd bump this thread to help me fix it, hopefully thats ok!

I must have tried every suggestion in this thread at least twice and loads of my own ideas to sort this problem out so any and all suggestions from anyone (especially with the same laptop) would be massively helpful

I'm so determined to sort this!!! Thanks for any help!

 

The best you can do with this machine is to get your DPC spikes to a minimum, but you can forget about eliminating them 100%, i'm sorry to say but it looks impossible after all I tried with mine.

Sent from my GT-I9300

 

Your right I really am so close now to accepting defeat on this one, I never thought I'd get rid of all the spikes but some of the major ones that make videos and music playback such a nightmare drive me insane! I might even get on the phone to acer now and their wonderful Indian help desk to see if that gets me anywhere haha! Last time they took my old laptop off me for 3 weeks and sent it back unfixed but desperate times, desperate measures they might be better this time!!

Thanks!

 

I was dealing with DPC spikes for about 4 years in total, the best you can do is to disable as much as you can in device manager, Wi-Fi, battery management, even the DVD drive, but spikes will never be gone. For a long time I thought that the solution was to disable dynamic FSB switching, thermal throtling, but since modded BIOS for 7720 came out it was clear that this is a hardware issue afterall.

Sent from my GT-I9300

 

I am sorry to say this, but if you need a machine without any DPC latency issues, buy a Macbook. I love Acer and I learned a lot from my 7720 about modding, fixing, upgrading laptops, but Macbook Pro was the thing I needed to work with music without problems, the way I wanted from the start.

Sent from my GT-I9300

 

You can also just buy a laptop of a better brand with integrated graphics and the likelihood of DPC latency issues is much less.

Maybe this can help, not sure if you've tried everything already though:
http://www.idmforums.com/showpost.php?p=839462&postcount=1

 

Nothing new to me in that link But, if you want your DPC spikes as low as possible you should go with XP rather than Win 7.

Sent from my GT-I9300