Re: XPS 15z Audio Crackling/Stuttering (Wireless Connection Latency Issue)

Hi All,

I have been talking to DELL Tech Support over the last few days about my problem and now after various rounds of testing, they have accepted the fault and have are now ready to replace my Motherboard. Do you guys think this will help?

Thanks and Regards,

Shiva.

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ShonkyCH
2 Iron

Re: XPS 15z Audio Crackling/Stuttering (Wireless Connection Latency Issue)

Read the threads and you will see that our answer will be a "likely not at best".

They gave me a whole new machine at once stage and it had the problem out of the box. So unless a new machine has an upgraded motherboard/wifi card it will still have the problem. It's not a hardware failure from all accounts so far. Unfortunately Dell do not seem to even acknowledge the problem and insist on going through there standard cheat sheet for fixing issues i.e. upgrade drivers, full reinstall, replace hardware etc.

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Re: XPS 15z Audio Crackling/Stuttering (Wireless Connection Latency Issue)

Thanks for the quick reply, ShonkyCH and Yes, I expected that. Even now, before giving away my laptop for hardware replacement, I have asked them in the first place that whether replacing motherboard will solve the problem or not and have they been successful doing that with other users. But it is quite frustrating to note that they are not ready to accept the problem despite so many of us experiencing the same. I think nearly 95% of all XPS laptops are affected and perhaps only 50-60% of them reported to DELL. Is it anyway possible to take this issue to the Next Level? After all we did not get the laptop for Free.

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James2k
3 Argentium

Re: XPS 15z Audio Crackling/Stuttering (Wireless Connection Latency Issue)

Myself and a few others have recently been communicating with Terry B (Dell notebook Liaison) about this problem and what Dell are doing about it (See the post by iAMjason on page one of this thread). To summarise the response. Dell is aware of the issue and its been reported to engineering which have apparently been reading these posts. Though it  seems engineering are taking a firm stance that Windows 7 is to blame.

I do not entirely agree with this statement and hope the information in this thread shows that it is more than just the operating system that is at fault. It may well be that Windows 7 is PARTLY to blame, but I don't think its the primary contributor to the latency issue.

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Highlighted

Re: XPS 15z Audio Crackling/Stuttering (Wireless Connection Latency Issue)

Great and good to know that James. I will read the posts and have been doing it as and when I get time. But if DELL is so confident that Windows 7 is to blame, then why can't they simply install Vista or XP on these (if it is supported well enough) and try to prove that they are right? Did they do that already and also have you guys heard of anyone else reporting the problem who is using Windows 7 and not DELL? At least I have Windows 7 Professional on my office PC which is Lenovo and that doesn't seem to have any problem whatsoever. The only difference in this one being No NVIDIA and webcam. Also I have Intel Centrino Advanced-N 6200 AGN wireless adapter.

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James2k
3 Argentium

Re: XPS 15z Audio Crackling/Stuttering (Wireless Connection Latency Issue)

All of the drivers for the XPS 15z are for Windows 7, there are no drivers for Vista or XP so its not possible to test another version of Windows reliably. However installling a Linux distribution is a option to see if audio issues still occur. Regarding a non Dell laptop and the Intel Centrino 6230 N, I have personally not seen any reports of problems so this may lend credibility to the fact Windows 7 is not problem.

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AKTundra
1 Copper

Re: XPS 15z Audio Crackling/Stuttering with network traffic over wireless (Latency Issue)

My daughter is having the same problem with her XPS 15z when she listens to audio over our wireless connection (wireless N). She tried Dell support and got no where with India tech support supervisor. He wanted her to pay $170 for a one year software contract to periodically clean her registry. He said it was not Dell's problem.

After much internet surfing I came upon a potential fix, not a solution mind you, but it seems to be working for her.

We downloaded the DPC latency program and while initially in the green, it went immediately into the yellow/red when she watched netflix just as you are experiencing.

I then went to control panel / hardware and sound / power options. Then for the selected power plan (I set up custom plan 1) click on change plan settings and then click on change advanced ower settings. Then click on processor power management and click on minimum processor state. Now you will probably see 5% for both battery and plugged in. I changed these to 55% and now when she runs netflix it stays all green.

I don't know if this will now cause other problems, other than probably reducing battery life, but it seems to solve her audio distortion.

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ShonkyCH
2 Iron

Re: XPS 15z Audio Crackling/Stuttering with network traffic over wireless (Latency Issue)

AKTundra

Cleaning the registry ain't gonna do it. Some people have experienced it with bare installs. I have verified it occurs with a brand new fresh image from the Dell recovery partition. If the registry was "dirty" then it's being provided "dirty" by Dell and hence should be their problem. However I think we all know that's not the issue.

Your work around sounds promising. Did you try any other values between 5 and 55%?

Yes I would expect battery to be significantly impacted. I assume this is clock speed or similar although I'd be surprised if it can drop down as far as 5% of maximum speed. That's only about 150MHz (can't remember the min max speeds). The Intel turbo boost doesn't tend to show speeds below the nominal maximum though.

Also if the device is running more continuously, I'd expect more heat to be generated resulting in the fans operating more further reducing battery life. Also that heat is not good for electronic components in general. Roughly half the life for every 10C increase in temp.

If setting to 10 or 15% was enough that might be an acceptable solution at the expense of some battery life.

NB: All my testing so far would have been on AC power but if both are set to 5% then they should operate the same.

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AKTundra
1 Copper

Re: XPS 15z Audio Crackling/Stuttering with network traffic over wireless (Latency Issue)

The registry answer from Dell India was clearly not valid. Her registry was no more corrupt than an average computer that has been in use for a couple of months with various software installs and uninstalls. I agree with you.

No I did not try any other numbers between 5 and 55. I did note that on my 6 year old XPS 1730 the default settings for the "high performance" plan were 100% plugged and 50% battery. This is the setting the laptop has been set to since I got it . Probably part of the reason this laptop runs so hot..of course two 9800M video cards in SLI aren't helping the heat issue either. LOL.

Battery  life is a non-issue on that machine since without its 'brick' transformer plugged in battery life is like 20 minutes.

I will have my daughter try lowering the settings and see what the sweet spot is. Before this change her laptop was very cool. It will be interesting to see if it starts to heat up at the 55% setting.

If this solution works, it is simple to put into effect as long as it doesn't create other equally or more bothersome side effects.

Cheers

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ShonkyCH
2 Iron

Re: XPS 15z Audio Crackling/Stuttering with network traffic over wireless (Latency Issue)

Ok. So I tried playing with the minimum CPU state. Monitoring using CPU-Z though there doesn't seem to be a direct correlation 

The slowest CPU-Z ever reported was 800MHz (8 x 100MHz) and the maximum was 3300MHz (33 x 100MHz). So 800 is about 25% of maximum speed.

My testing showed there didn't seem to be any noticeable difference between 5 and 25% in terms of red bars in DPC latency.

40% was better in terms of red bars but still quite a lot. CPU frequency was still dropping to 800MHz

Around 50-55% is where it really starts to kick in and help a lot. Mostly yellow/green bars and all less than 4000us (small red readings every now and then). Probably this would be good enough assuming battery life wasn't significantly worsened. In this setting CPU-Z still reported 800MHz speeds but they seemed less frequent and generally would sit on 1600MHz or higher. I didn't see a correlation between bad latency and 800MHz though.

At 100% it was much better and green nearly all the time with an occasional yellow. No red ever that I witnessed. Processor still dropped back to 800MHz

At the higher minimum percentage state, the fan did seem to be running a bit more than normal but not excessively as I had suspected in might end up doing. It definitely seemed to get hotter with it on my lap.

So to summarise, increasing minimum process state does help but I'm not really sure what that really does and what adverse effects it might have. The most likely is worse battery life but would require more testing and timing of battery life.

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