Weighing in on the DPC latency issue (as seen on Engadget)

Hello, all!

There’s been some buzz recently concerning DPC latency on the Alienware M17x, et al, and I know it has been a concern to your community. I just thought I’d drop you guys a line to let you know that not only is Dell aware of the issue, we’re currently doing a deep dive on it and looking for solutions.

I recently posted on Direct2Dell concerning the issue here:

http://en.community.dell.com/blogs/direct2dell/archive/2009/11/18/dell-dpc-latency-and-you.aspx

As progress is made, I’ll be reporting back to the gaming community at large on that post, so feel free to drop by there for updates!

-John Blain, a.k.a. JohnBatDell, a.k.a. the Dell Gaming Guy

Edit: typo resulting in a seriously redenned complexion

 

Thanks for the update, John - please keep us posted!

 

"Some folks are using tools to measure DPC latency, and while measuring it is one thing, it may not actually cause performance issues."


Hi John, just for your information im not one of those who use tools to measure DPC.

The current situation with the M17x is that it is un useable to play any mp3 through windows media player, or nero.

this isnt a minor irritation this is a product that fundementaly doesnt work.

This would be like buying a mobile phone that every 30 seconds dropped the call and you had to redial.

the thing is this isnt a normal phone this is advertised as the fastest best phone in the "universe" and cost you more money than any other phone!

you would be kind of anoyed!

 

The biggest spikes seem to come from the second SLI video card downclocking, and that causes stuttering. Disabling powermizer only works for the primary card, but the second still clocks down and causes these huge spikes (and I mean huge - off the charts on the DPC Latency checker) that actually seem to cause the most severe problems (framerate drops in games, videos, sound crackling/stuttering/skipping, etc.).
But DPC latency is very bad otherwise also especially in Windows 7, even without the spikes. I believe the big, noticeable spikes in games could be alleviated if the videocards were prevented from downclocking, however.
There really needs to be a fix for general latency, however, which is imperative for professional audio and video editing.

 

As I said in the blog, the latency may not cause performance issues. I have an M17x myself, and I haven't seen anything like the trouble with WMP you reference.

But like I said... it "may not" cause issues... the mileage may vary due to config... so conversely it "may" cause issues as well. :-(

We're digging into it, and have been. I'll post answers as they come :-(

 

I have tried reinstalling several times, tried to use all the recomended drivers in the correct order.

I'm just wondering now wether i can get hold of a windows7 re spawn disk distributed with current systems.

 

Knock on wood, i'm in the same boat as John. I have no noticable stuttering in anything i do. Gaming, playing music, watching movies, etc

And except for updating my video drivers and installing my Supertalent Ultradrive SSD i have a pretty basic model and havent tweeked anything in the system, except OCing my CPU to 2.4gHz once to see if i could.

 

Mind posting your M17x config?

 

I don't have it with me (I'm in the office) but if I recall correctly I have a Dual GTX280M, T9800 Proc, 1TB RAID 0, and I'm running Vista Ultimate.

 

i suspect thats because of raid/seagate hdd. for example i have non raid 2x320 gb WD drives and i've never seen any stutter with audio. BatBoy also has't any audio stutter. so this problem hve some m17x owners but not all

 

My latency issues dropped dramatically when I moved from win 7 to Vista.

 

Yeah same here, Only really had big problems when i installed windows 7.

 

The worse part is all the new ones only come with win7. So right out of the box these things have known issues and for the life of me can't under why Dell continues to sell them knowing there are major issues. I'll be honest, when I opened up mine with Vista 64 on it and installed a game on the image that came with it I had insane gaming issues. I switched to Win7 hoping to solve them and still had problems. In a last try effort I did a fresh install of Vista 64 and thankfully the problems are down to a minimal. I still have issues while gaming, just not as bad. Still in my eyes not worth $3k+.

People are buying these new ASUS gaming laptops for a little over $1500 and are loving them.

 

Hi John,

The issue is MUCH more severe on Windows 7 than it is on Vista. I have Vista running now and i dont have much latency issue anymore. But i still notice audio cracking every now and then cause by latency spiking very high.

But on Windows 7 its on a different level..... It is MUCH worse on W7. I couldn't stand it and went back to Vista.

 

it''s nice to see that dell cares at least.

 

I don't believe RAID is the cause. I opted for a non-RAID setup from the start and did encounter the intermittent audio popping/skipping issue initially with my system. Intermittent FPS stuttering/drop off was also an issue. After using my work-around (detailed here), I no longer experienced this symptom. This has worked for a few others as well. FWIW, I have stayed with Vista so I cannot comment on W7.

If possible John, please pass this info on to your engineering folks for review. Thanks again for posting here and keeping the AW community updated on developments.

 

I have win7 non raid setup, its not raid related!

 

Definetly RAID is not the cause of this. I have one HDD and i experienced massive stuttering with WIN7 and minor stuttering in Vista.

 

I'm glad Dell is aware of this and working on it.

 

The Dell guy makes it sound like it will be corrected with a simple software update or driver update but will that really be the case???

What happens if it's a hardware update? Are they going to change all the M17X?

A major PC recall...

 

You can recall my M17x over my dead body

/runs off and plays gta4

 

I have never had any issues. But my system is a clean install and not a stock ...

 

Mine is M17x, Q9000, single SSD, Windows 7. I see latency issue when checking it with DPC Latency but I only experience audio stuttering while Im surfing web using FireFox (change, open, close tabs...) with Hybrid SLI Boost Performance enabled. Switch to Save Power mode in Hybrid SLI and audio playback is so smooth. And I have never experenced gaming stuttering.

 

Not all games stutter. In fact most of the big titles dont. I find that almost all games from Capcom does stutter (RE5, SF4, DMC4). Some stutter worse than others. Its not consistent.

 

just an FYI, they've found some root causes, and are working on BIOS updates to fix. I've updated the blog post on direct2dell.

 

I used RAID with Win7 and regular with Win7. Aside from the slower loading times, non-RAIDing the hdd's drastically decreased the audio pops and crackles to the point where listening to mp3's was tolerable and almost completely unnoticeable.

I also found that simply typing into Internet Explorer (like this post) would increase latency quite a bit. This problem seemed to go away completely when I reinstalled W7 without RAID.

I honestly believe the software RAID controller could be contributing to this problem.

 

I'm glad to hear Dell is working on a fix for this that involves something basic like a BIOS update, a chipset driver update, or a sound card driver update.
My bran new uber computer can't even play a YouTube video right. Given the extent to which this issue is covered on this forum, I don't think I need to go into much detail to explain that this problem has nothing to do with you tube and has all the tell tale signs of being a much more universal and basic issue. It happens on all the audio I have tested so far, and although it is nowhere near as definitively evident, I do suspect that something similar may be going on with video. My 333mhz Pentium II based machine ran multimedia better than my M17X. Needless to say, I am very:

My original order was canceled because of a supposed Adobe Reader conflict, and I was not contacted about it. Months later now that I finally received the machine, I see that the engraved nameplate on the bottom is truncated, which I pointed out to the person re-placing my order. I skipped the space between the two words when I put the order in myself, but he assured me it was an order interface issue, and that it would come as requested on the final product. Wrong. But that is the least of my worries. I would be glad to never look at the nameplate again, if I didn’t have to keep flipping the computer over to get the service tag in a vain effort to solve this stutter glitch.
Please let me finally take some pleasure in having ordered this machine Dell. Please fix the Audio / stutter glitch! I see no applicable updates on the download site yet.
/end_rant
John@Dell: Thanks for your contributions towards resolving this. We look forward to future updates in here and in your other thread.

*edit*
After my first real night of gaming on this machine, it is clear to me now that the issue affects video too.
/end_edit (12-3-09 8:18am)

 

Does this DPC latency issue affect system lockups too?

 

Guys they're fixing it !
Celebration time cmon!!!


Looking forward to the update John..

 

I will celebrate when the fix is out and it has solved the issue. Don't want to be a party pooper but I was expecting this laptop to work PERFECTLY from day 1.

It still amazes me that we are the ones that discovered it. It's a gaming laptop! Didn't they test it before releasing it to the public?

Anyway, now I want to see the fix before jumping up and down.