[*Unresolved* Issue] Alienware M18x: GTX 580M SLI DPC Latency Problems

[Mr. Fox]

UPDATE 02/21/2012: Please install Verde 295.73 drivers and implement the tweak posted here or here.

It is a rude awakening for anyone to discover that their Alienware flagship M18x beast is unsuitable for performing a task as ordinary as handling real time audio because of an unresolved driver bug. It's unfortunate that something correctable like this continues to be the Achilles heel of an otherwise incredible machine.

This thread was started for discussion of the DPC latency problem the M18x exhibits with GTX 580M SLI. I moved a number of my own posts into this thread to consolidate the information for Dell's benefit. Those are consolidated in the post below. If you're not familiar with DPC latency first hand, you don't want to be. You can read about it here. For me, this will usually manifest itself as strange clicks and pops in audio, and might be what causes what I like to refer to as the "cyborg" electronic distortion type of sound. I seem to get that randomly while gaming and sound sometimes ends up looping followed by a system freeze that coincides with that audio glitch. It does not happen all the time, but it happens enough that I don't forget about it.

It appears this issue does not affect systems equipped with AMD 6990M CrossFire. Additionally, DPC latency does not appear to be a problem running Dell's recommended driver (269.03).

Using Dell's NVIDIA 269.03 driver is OK with me for the moment, but it is starting to get a little long in the tooth and we cannot keep using it forever. We need to know what is causing it and how to fix it. Is it something Dell tweaked to correct the problem with their 269.03 driver, or is the DPC latency being caused by something NVIDIA changed in drivers released following version 269.03? Hopefully, Dell/Alienware can shed some light on this for us and produce a solution. If the reason is not known at the present time, then we can include this as an agenda item on the next conference call.

Here's where the assistance of the Alienware M18x Community is needed...

Before we can expect a fix, it needs to be established that an issue exists that needs to be fixed. If you own an M18x with GTX 580M SLI, please download LatencyMon from the Resplendence web site, run the test for 3 to 5 minutes and see if your test results are similar to mine. Please post your results and specify what driver you have installed.

When posting screen shots, please be mindful of forum rules. Images that are too large will be removed, and posts that don't make any sense without the image to reference will be deleted. Please use thumbnails or spoilers, upload the image as an attachment, or resize the image.

• Please do not post huge images. Anything over 500x500 should be thumbnailed or linked only. See our guide for where to host images here and how to resize images here
  

Thanks in advance for your testing and reporting.

[Mr. Fox]

I was hoping A05 would help with DPC latency, but it did not. Maybe this can be the next thing to be resolved. I'm going to start pecking away at finding the cause of that issue so we can get it fixed.

Spent a little more time trying to find the source of the M18x DPC latency. Initial tests pointed to the NVIDIA drivers. Seems I confirmed that today. I did a clean uninstall of all NVIDIA software, checked latency and reinstalled Verde package. See below...

DPC Latency - No NVIDIA Drivers (Standard VGA Adapter, Windows Hi-Def Audio)


DPC Latency - NVIDIA Verde 290.36 beta (same result with Verde 285.79 driver)


Not sure yet if it is the NVIDIA hi-def audio driver or display driver. May try with standard Windows 7 hi-def audio driver to see.

I found no changes after removing the NVIDIA hi-def audio drivers. I'm not sure if that is what you meant in your post with the 2 thumbnails. Am I understanding correctly that DPC latency is running high on your system with the unlocked A03 or am I misunderstanding?

I ran a series of tests... there's good news and bad news.

Good news first... Dell's "recommended" video driver fixes the DPC latency. I installed the Dell beta 285.62 and Dell recommended 269.03. So far, all Verde drivers except Dell 269.03 have high DPC latency. Just to be sure, I reinstalled them a second time after 285.62 and the other reference drivers, and sure enough, the Dell 269.03 has zero DPC issues.

Now the bad news... 3DMark11 and Vantage scores drop using the only driver without DPC latency. So, I am going back to the NVIDIA Verde reference drivers. The DPC latency irks me a little, but other than discovering it with the LatencyMon utility, I perceive nothing adverse while using the system. There are no symptoms from the DPC latency that I have noticed.

In the process of all the testing, my NVIDIA Control Panel systray icon is AWOL and I cannot figure out how to turn it back on again. I'll Google for that. Below are the screen shots from my testing.

Spoiler :

No NVIDIA drivers installed - Standard VGA and Windows hi-def audio

Dell Recommended 269.03 Driver (no DPC latency issues)

Dell Beta 285.62 Driver (major DPC latency issues)

Dell Recommended 269.03 (installed a second time - no DPC latency issues)

I did test this with 6990M crossfire, and the AMD don't have DPC latency.

I ran through a series of tests and the GTX 580M SLI setup has zero problems with DPC latency while using the Dell 269.03 display driver. The image below is at system idle when using the Dell 269.03 driver. I continued allowing LatencyMon to run and finally shut it off at 45 minutes. I never once had a spike.

I've checked this like 5 times now over the course of a couple weeks and every driver except Dell's is off the charts with DPC latency. (The Dell NVIDIA beta does poorly, too.)

[skygunner27]

You are absolutely on to something. I have also noticed this problem for some time and have the same results.


Sent from my iPad 2

[vanhausse]

Yep I have it too, although I wasn't even aware of it until I read it. =p

[Mr. Fox]

Please post screen shots of LatencyMon showing the problem (compliant sized images) and a short note indicating which driver you are using.

What prompted me to change my mind and go back to Dell's driver was issues with games crashing/freezing. I'm going to test the Dell drivers further to see if it helps with that. I did not perceive any issue from the DPC latency originally, but I may have concluded that in haste. I think these two things are related because the freezing is usually preceded by a stuck audio loop for 1 or 2 seconds. This does not happen daily, but it happens randomly more than enough for me to want this issue fixed.

[5150Joker]

I'll run the check in a few minutes after I get done installing arkham city. Do we need to make sure nothing is running in the background before doing the test? I think I read somewhere that if the CPU is active the dpc latency goes down?


Edit: Ok its just what I thought. When I have the nvidia control panel open with an active 3D nvidia logo, the DPC latency drops WAY down to normal levels. So as long as it drops during 3D gaming, I don't really care what it does in 2D. See attached photo.

Driver used: 290.36 beta

[Sentinel196]

Here's my results on 6990Ms with Wi-Fi on (bad latency), and with Wi-Fi off (good latency)

[steviejones133]

Latency Issues here too, with my 580sli system & Nvidia Drivers.

Spoiler :

EDIT:

I too noticed exactly the same as Joker - with the CP open, latency remains at or around sub 200....

Spoiler :

[Sentinel196]

Can someone run it in th ebackground on a 2nd monitor with a game running on the primary?

[steviejones133]

Can someone run it in th ebackground on a 2nd monitor with a game running on the primary?

Just done that - other way around though. Game on my external and monitored on the laptop internal. Played Crysis 2 for a litte bit and latency seemed to hover within limits around 200us. After gaming for 5-10mins, and monitoring from the outset, the message was that my system was good to handle real time audio etc.

I repeated the process so the game was on the internal whilst I had the monitor on the external with extended display. Same result, all seemd ok to me.