Update from Lionel: Below is John's original post on the topic of DPC Latency. Here is John's second post where he outlines the fix. To centralize the discussion, I closed comments on this post. If you have comments, please leave them at the updated post.
You may have seen some chatter recently about an audio issue on the Alienware M17x on Engadget, NotebookReview and Dell’s Community site. The discussions revolve around deferred procedure call (DPC) latency, and its affect on audio performance. We are aware of the issues customers are reporting, and are currently working to address them.
Some folks are using tools to measure DPC latency, and while measuring it is one thing, it may not actually cause performance issues. The few customers who have symptoms are reporting the following:
- Audio stutters, clicks, pops, and drops
- Frame drops while watching videos
- Audio/Video desync during video playback
DPC latency is not an issue that is specific to Alienware or Dell. This is a complex problem to address, and there are no simple solutions. DPC latency can be caused by numerous issues including the system BIOS, a sound card or audio chipset, drivers, the operating system itself or a combination of those things.
We will continue to dig deeper into this. As we make progress on this issue, I'll report it here.
Update, 11/25: I just received a report from our engineering teams that the problem has been reproduced and has been narrowed down to two possible root causes. I should have more news for you next week!
Update, 12/2: Some good news! The engineering team has successfully recreated the problem and identified several causes. One root cause has been identified and can be addressed by a BIOS revision, and an updated BIOS is now being validated. The engineering team is hopeful that the other root causes will also be resolved via a BIOS change, and are working to confirm this so a full BIOS update can be implemented.
Update, 12/15: Sorry there hasn't been anything concrete to report, but I finally have something. My friends in engineering informed me this morning that a fix has been written and is now in the final testing phase. I've been assured that the fix will be ready for consumption in the next couple of weeks, barring any unforeseen incidents!
Final Update: Many of you have noticed the A03 BIOS revision has been posted on the drivers and downloads page. After installing this BIOS revision, please make sure you have the latest Broadcom wireless driver from the support page. These steps should resolve the issue for most users.
For those still having problems after doing the above, please contact technical support for further assistance.
Thank you so much for all of your patience. I apologize for the wait!
Update, 1/18: Just wanted to know this story isn't quite over yet. NVIDIA and Dell engineers are working together towards a driver fix, and this I was told today. I apologize for any confusion. Hopefully we can come to a complete resolution very soon. I'll update you as I hear more.
Update, 2/12: After participating in a conference call with the internal key players regarding this issue, I'd like to invite those who are still seeing this problem to message me personally with their service tag and case information, as well as a description of what you've done with support to try to resolve this issue since it began. I'd like to get that information into one place so we can expedite a resolution for those affected.