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M17x and DPC Latency

post #1 of 80
11/17/09 at 11:04pm
Thread Starter 
Have any of you M17x owners run into audio or gaming stuttering issues? This seems to be a problem for more than a few folks in other forums, but I don't see it being discussed here in these forums. Some people are severely affected, others not so much. There seems to be no rhyme or reason regardless of chip or GPU configs.

DPC latency checker software can be downloaded from http://www.thesycon.de/deu/latency_check.shtml. I'd be interested if those who have an M17x could run this real quick and maybe post some screen captures.
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post #2 of 80
11/17/09 at 11:28pm
I know someone mentioned that game play was lagging when the on board GPU was enabled.

I found the same thing, when I had the 9400 and the GTX280 cards enabled.

So I disabled the 9400 in the BIOS and it fixed any issues I have had so far.
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post #3 of 80
11/17/09 at 11:42pm
I don't hear any audio stuttering. I can see this being a huge issue for those that record music.
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post #4 of 80
11/18/09 at 12:01am
Thread Starter 
No doubt. For them the machine is basically a paper weight.

BTW, here's one screen shot of DPC latency checker from an affected M17x.
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post #5 of 80
11/18/09 at 9:24am
Someone should run this test with the cpu under a load or even OC'ed. See if this is the result of the CPU down-clocking. I'm not at home currently to do it.
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post #6 of 80
11/18/09 at 11:11am
Thread Starter 
I would, but I don't own an M17x (yet).

Other forum threads point to the down-clocking of the video cards as one culprit. For the nVidias, one solution working for single card owners has been to disable Powermizer, but for the SLI setup, this doesn't work because it only impacts the primary card. The 2nd card continues to change clock speed. This also doesn't help owners of the ATI crossfire config.

Finally, DPC latency has been impacting many other Dell laptop models. Here's a thread regarding the Studio 1737's problems with DPC latency. Note the message posted (09 Nov 2009 09:10AM) by Bill-B, a Dell employee, mentioning a bios fix that's currently in testing.

It's refreshing to see a knowledgeable company rep communicate directly with its constituency. More companies should make that standard procedure.
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post #7 of 80
11/18/09 at 11:24am
That's a Dell owned forum. I would hope their techs would be there.

If down-clocking of the cards is suspected then just flash the "under clocking" values and disable powermiser (if it isn't already).
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post #8 of 80
11/18/09 at 6:22pm
Hello,

My name is Richard; I am the Dell/Alienware laptop liaison for the Dell Community forums. For those of you who are experiencing audio issues which have been suggested to be related to DPC latency; I wanted to provide you an update.

At this time we are investigating how DPC latency could be causing the following reported symptoms.

- Audio stutters, clicks, pops, and drops
- Frame drops while watching videos
- Audio/Video desync during video playback

We realize how important it is for our customers to be informed. You will be updated as soon as possible when we know for sure what is causing this issue and how to correct it.

For more information please refer to our blog statement.

Best regards,

Richard Bernier
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post #9 of 80
11/18/09 at 6:45pm
Thread Starter 
Great news that the awareness has reached a critical mass.

Hopefully there will be a complete fix soon. I'm ready to fork over $4,500 of my moolah to purchase a decked-out M17x, but I won't do it until I know this problem is squashed for good. Until then, I will limp along on my old Aurora m7700a.
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post #10 of 80
11/19/09 at 5:32am
Hi Richard,

I was just reading the dells blog link in your sig. I'm sure that you have gone through this post here. Mostly what we have found about the latency spike issues were analyzed by many posters here and it comes down to two reasons.

First one that causes the massive spikes (mostly 16k+ can reach to 200k) is due to the GPUs changing their clock speed. You can clearly see this if you run the DPC latency check and any GPU clock reader(GPU-z) and run any graphical game. You will notice the spikes occurring every time the GPUs change the clock speed(down, or up).

The other reason is more complicated i think. It revolves around the ACPI process, and we are not sure what is causing it to spike up to 4k.

If you are reading this i hope that you guys will figure out the issue. It is more severe on Windows 7 than on Vista by the way. And i cant believe that the testing team and quality assurance team did not catch this.....

More info can be found at the notebookreview forum, im not sure if im allowed to post a direct link to there
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post #11 of 80
11/19/09 at 6:34am
Quote:
Originally Posted by Rotsu View Post
Hi Richard,

I was just reading the dells blog link in your sig. I'm sure that you have gone through this post here. Mostly what we have found about the latency spike issues were analyzed by many posters here and it comes down to two reasons.

First one that causes the massive spikes (mostly 16k+ can reach to 200k) is due to the GPUs changing their clock speed. You can clearly see this if you run the DPC latency check and any GPU clock reader(GPU-z) and run any graphical game. You will notice the spikes occurring every time the GPUs change the clock speed(down, or up).

The other reason is more complicated i think. It revolves around the ACPI process, and we are not sure what is causing it to spike up to 4k.

If you are reading this i hope that you guys will figure out the issue. It is more severe on Windows 7 than on Vista by the way. And i cant believe that the testing team and quality assurance team did not catch this.....

More info can be found at the notebookreview forum, im not sure if im allowed to post a direct link to there
You can post your own observation and remark, using what you learn and read anywhere else. The link to NBR as you mentioned is just another discussion, like members here are doing.

You are welcome to invite (privately) the members there to come here and joining the discussion here. Have you tried to link "this" thread in NBR and see what happens?

cheers ...
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post #12 of 80
11/19/09 at 2:26pm
Thank you for the replies.

We have software and hardware engineers working on this. I can confidently say we are aware of your findings. We are making sure that the actual cause of the issue is the results you outlined and not some other unknown.
Basically, we want to get it right for our customers.

Greatest regards,
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post #13 of 80
11/20/09 at 3:08am
Glad to have a response on this Richard, and all of the individuals from Dell. I have been working the issue for quite a while and I'm going to agree that it "may not" necessarily cause issues as stated, but something certainly is and one of the side effects is displaying itself as an enormous spike in DPC Latency, 15k to 150k us. Either way, I'm glad to see a bit more community information getting out.

Aedaric
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post #14 of 80
11/20/09 at 3:57am
I see the DPC latency issue. I also have a/v stuttering when playing games, and streaming videos. I get random pauses (with audio stutters) ranging from 1 -5 sec in windows 7 64bit. The stutter seem to have a corresponding DPC spike of 60k + in the latency monitor. I see the problem with both ATi 4870 (single/crossfire) and Nvidia 280 GTX (single /SLI). Changing the clocks on the CPU or GPU has no affect.

The only way I have found to correct the a/v stuttering is to change the IDE controller from the " Nvidia Nforce Serial ATA controller" to the builting OS driver "Standard AHCI 1.0 ATA controller". Doing this has nothing to do with the DPC latency issue but it does correct the a/v stuttering problems. The DPC latency will still be be high.

Zyb
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post #15 of 80
11/20/09 at 4:38pm
Quote:
Originally Posted by dave-p View Post
I know someone mentioned that game play was lagging when the on board GPU was enabled.

I found the same thing, when I had the 9400 and the GTX280 cards enabled.

So I disabled the 9400 in the BIOS and it fixed any issues I have had so far.
i can't get as far as the gpu in bios set up but it wont let me highlite the 9400 to disable any thoughts?
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post #16 of 80
11/21/09 at 9:41pm
in the bios set both to disable the GTX cards will be the only ones you will see in Windows
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post #17 of 80
12/3/09 at 11:31am
As an update, It looks as if Dell/AW have recreated the problem (finally) and should be coming out with a fix fairly soon..

They are posting updates here.
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post #18 of 80
12/3/09 at 5:21pm
Wow, we got a guy from Dell/Alienware on the boards again! This is good to see!
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post #19 of 80
12/3/09 at 6:27pm
On NBF? They're always around.
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post #20 of 80
12/5/09 at 5:19pm
Interesting find...

With a QX9300


With a T9900
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