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How about that latency problem with studio laptops?
Hi guys,
After almost a year of annoying myself over my dell studio laptop and it's crazy latency problems I though to give it another go at the Dell Forum. Is there any know fix for this widespread problem. I am a windows 7 user and couldn't really find a fix for this searching google.
Would like to hear from you guys.
Cheers,
Jon
Jim Coates
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March 21st, 2011 11:00
A problem with discussing the DPC latency issue is that it is one symptom with a number of possible causes, both software and hardware. It can be caused by a poorly written driver and perhaps not even have anything to do with Dell. Or it might; I am just pointing out some of the complexities. For example stan_-_ wrote that he has "same problems", but it might be that he has the same symptoms caused by a different problem than the problem causing the symptoms on JonHil's laptop. (stan_-_, you are using the Latency Checker tool. There are instructions on the tool's web page on how to use it to isolate a driver that might be causing the latency. Also if the latency is cyclic it is likely caused by by a device or program functioning at specified intervals.) Most of my knowledge of the DPC latency comes from 2 threads:
Studio 1737 DPC latency thread started June 13, 2009
and
Studio XPS 1340 latency thread started Feb 23, 2009
The main models that were affected at that time were the Studio 1735, Studio 1737, Studio 1535, Studio 1537, and Studio XPS 1340, and some Vostro models. Perhaps Studio 1555 also.
Over the years I have not known Dell to put much of its resources into trying to fix existing audio problems; they seem to put out a new laptop model about once a month and probably have their hands full just thinking up names for all of them. Once a model is in production no doubt they are already deep into developing future models. However, in this one instance they did try to fix the problem, for 2 reasons in my opinion. One was that the Studio XPS line was a new premium line that they wanted to work right, and the other is that one of Dell's people with some pull got involved and pushed for a fix for 14 long months. The history of it is this.
Dell came up with a BIOS revision (11) that fixed the dpc latency on the Studio XPS 1340 model, as long as the units were configured with Intel WLAN cards and not Dell (Broadcom) cards. Encouraged by that success, the engineers plan was to get a BIOS fix for the Studio 1737 and then apply that knowledge toward a fix for the other models, but that never happened. The A07 BIOS was released in Sept '09 and it was supposed to be the fix, but it was a big flop. They re-worked it and released A08 almost 3 months later. The Dell guy who was the communication pipe between the posters and the Dell engineers was Bill B, who a couple of months later wrote:
"The last word I got was the 1737 has a design limitation that prevents latency issues from being resolved. The platform has transitioned to a new engineering team. The new team reached out to me asking for feedback on the recent BIOS release. I let them know it was in no way a fix, and passed on a couple of choice recent comments from this thread." (The Studio 1737 latency thread)
That was just about Bill B's last post on the thread. It has been 13 months since he wrote those words but no one from Dell has ever reported back what the "new engineering team" did with the problem. My guess is that the engineers had shot their wad with A08 and just gave up on it after that -- so no hope for the 1737 or 1735, much less later models which have dpc latency but whose root cause could easily be unrelated to the earlier models. As seen, the fix for the XPS Studio 1340 did not translate into a fix for the other Studio line, so there never was a chance of a single solution. Bill B claimed that the models released after the Studio 1737 did not have the same designed-in dpc latency problems as the ones before, which if true gives hope that on later models it is a driver or wireless issue.
One thing that came out of all that was that certain wlan cards are a source of dpc latency regardless of whether there are other causes on the same computer. The worst offenders are the Dell branded cards (Broadcom), particularly the Dell 1515.
Also of interest, there is a workaround solution for the Studio 1737 developed by DJQuartz, that involves suspending ACPI under Win XP using Process Explorer. Some people got it to work in Vista and 7 using Process Hacker. The engineering team was convinced that the dpc latency was caused by the hardware design of the system board, but Bill B thought they were wrong because of DJQuartz's workaround.
Another workaround was to create a hackintosh, by running Apple OSX on the Studio 1737. That worked because DPC is a Windows procedure (that creates much latency with a poorly written driver) that is not in the Apple OS or Linux. If you want to get a Mac you could try this. The problem will be in getting drivers for your computer that you can install.
So to summarize:
> there are different causes for dpc latency even on the same model, much less across model lines or manufacturer brands -- it is not just a Dell problem
> there is still uncertainty as to the basic nature of all of the underlying causes of the problem
> there are some causes that Dell just does not know how to fix despite much time and effort -- you would have to read the entire Studio 1737 latency thread to get a feeling for the amount of effort
> there is no hope for a Dell fix on existing models in my opinion (I could be wrong)
> some of the causes are user fixable. A couple of months ago DJQuartz reported that the dpc latency spikes are now under control on his Studio 1737 even without using his ACPI workaround, with the latest drivers and BIOS revisions. He has latest Intel Chipset, wireless, network adapter and touchpad drivers. He is still using XP which is the best Windows OS for audio work.
Jim Coates
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March 18th, 2011 19:00
Jon,
That's a dead horse. There is nothing new and will not be. What model do you have?
stan_-_
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March 20th, 2011 08:00
Hi,
same problems with my Latitude E6510. Latency Checker shows up to 2000 ms delays all 60-100 sek. Frustrating...
peace
Stan
JonHil
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March 21st, 2011 05:00
Unbelievable! Can't imagine the way Dell is treating this problem. My Dell studio 1550 (i think) got a new motherboard and everything else is replaced but still it doesn't work. Best solution will be to try and sell my laptop and buy an apple!
stan_-_
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March 24th, 2011 03:00
Hi Jim,
thank you for your particular answer! I am certainly aware of complexity of those issues. :-)
Nevertheless I used to think that the responsibility of the quality of a product is on the side of the "end"-manufaturer.
Only to complete the picture of my case:
Laptop: E6510, Windows 7.
The latency average is ~1000 ms. All bars are yellow! That means - each request needs too long! Comparing with my previous (not Dell) laptop - ~65 ms.
I tried allready to disconnect all external devices, deaktivate all relevant devices either in BIOS and in the Windows Device Manager. Under Windows Performace Settings - "optimised for background processes". No effect!
Cheers,
Stan
Jim Coates
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March 24th, 2011 06:00
Stan, my main purpose was to explain that excessive DPC latency is a symptom of a problem for which there can be more than one root cause. I did not mean to exonerate Dell. Over a year ago Bill B wrote, "... satisfactory DPC latency performance is now required before any consumer system goes to market." The responsibility is clearly on Dell to not sell computers with excessive DPC latency at the time of sale.
stan_-_
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March 24th, 2011 09:00
Jim,
I appriciate your support! Please don't consider this message against your words. :-) It was more a kind of a message to Dell, if somebody of gues who can be responsible for those issues read the topics on theirs own website.
Cheers
Stan
JohnReam
43 Posts
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May 5th, 2011 10:00
The BATTERY.
On our E6500, the DPC Latency Checker is all RED bars and the Laptop is effectively unusable slow.
Remove the BATTERY, and everything returns to normal, and the DPC Latency Checker is all GREEN bars.
We don't know why this started happening about a week or two ago. Maybe a Windows Update, since we generally keep up-to-date. Might also be Dell Website, for our E6500, update for Intel GIG Net card, which we did apply a week or two ago.
John
Ashville.Guru
3 Posts
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May 13th, 2011 23:00
I have a Latitude E6510, and I've finally (after much trial and error) managed to solve the DPC latency spike issue! :emotion-1:
Hope this helps. Of course, this probably compromises eSata functionality - so this perhaps qualifies more as a workaround. But for those stuck with this machine and needing it for pro audio... Dell has ensured that you can't have the cake and eat it too.
:emotion-45: to Dell for putting pro audio users through this nightmare. I would NOT recommend Dell for pro audio, until they get their act together.
Cheers,
Guru
Jim Coates
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May 14th, 2011 12:00
Guru, thanks for posting and sharing your solution! Most of the good answers come from people who try different things until someone works and then share that.
You might want to start a new thread with a subject line that would be easy to find with the search engine. If you make 2 posts in a thread, you can "mark as answer" the 2nd one which might make it easier to find. This forum lacks good search utilities.
I wonder if your solution would help the Studio owners? Those models also have a SATA port. You might post in the main Studio 1737 latency thread that I think I linked to earlier in this thread.
stan_-_
8 Posts
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May 15th, 2011 05:00
Hi Guru,
That works!!!!!!
Many many thanks!
And you are right - it’s shameful for Dell to release such buggy products!
Cheers,
Stan
woodslanding
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June 22nd, 2011 21:00
Clarification of the above: "that machine", my previous one, running XP SP3 with low latency, was a Lenovo R61.
woodslanding
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June 22nd, 2011 21:00
Hi!
Ihave an e6420 I just bought specifically for music. These problems are especially frustrating when dell seems to be the only company making a touchscreen laptop! I gather they must know of some other niche market that would have use for a touchscreen laptop, but certainly music is a big one. Sad then that this machine can't do a better job of it. I got better latency with my Inspiron 8600 A DECADE AGO!
Still, this post gives hope.....
I tried to make this change in the bios (rev A04) and the computer bluescreened on startup.
Windows startup repair could not fix it. I reverted to RAID, and it is working again. I'm wondering if there is some driver I would need to have on the system to allow the computer to start up after a shift to AHCI mode?? I have spent the last two weeks installing dozens of audio plug-ins and drivers for my system, and don't look forward to re-installing them all (especially the sample libraries that require me to load gigabytes of redundant data off DVD....)
And before doing all that, should I just plan to install XP SP3 again? I had my latency down to 64ms on that machine, with the processor running at 60%. I can't get 512ms to work on this machine without crackles even with CPU at 3%..... how much of that is attributable to XP??
Any tips or help welcomed!
-eric
woodslanding
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June 22nd, 2011 22:00
oops--correct!
woodslanding
10 Posts
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June 22nd, 2011 22:00
Okay, I found a solution to the problem of not being successful in changing the BIOS setting from RAID to AHCI:
http://answers.microsoft.com/en-us/windows/forum/windows_7-hardware/changing-from-raid-to-ahci/4c94f678-6bd1-48a6-b871-8872c841023a
hope this helps somebody else!
-e