Dell releases new XPS 15 9570 BIOS to address DPC latency issues

Well done, Dell. Nearly two weeks ago, the company promised to release a new BIOS for the XPS 15 9570 in the first week of May to fix the machine's ongoing DPC related latency issues. We are pleased to report that Dell has delivered one-day earlier than expected, and BIOS 1.10.1 is available to download now from Dell Support. You can find the download page here.

For those of you who have not read our previous articles, DPC, or Deferred Procedure Call, allows drivers to execute tasks and the system to prioritise them according to their importance. Buggy or poorly written drivers can eat up resources by making numerous DPC instructions, which can then cause audio stutters and glitches as the system struggles to prioritise audio playback over multiple instructions from other sources.

Many XPS 15 9570 machines have been suffering from DPC-related latency issues since it launched last year. It appears to have taken changes to its BIOS and driver updates to fix, or at least minimise, the issue. The new BIOS brings Dell Dock Station WD19 support to the XPS 15 9570 too.

We have not had a chance to test the new BIOS yet but initial reports online have been mixed. Some users have reported that the BIOS has reduced audio glitches and ACPI.sys DPC latencies from "around a max of 1.7 ms to around 0.6 ms. So, Dell has drastically reduced latency times by bringing them below 1 ms, but they are still above 0.5 ms or quicker, which DPC Latency Checker sets out as being ideal for glitch-free audio playback. However, one person has also remarked that the new BIOS makes audio sounds quieter than previously and that occasionally voices "sound robotic" before going back to normal after a few seconds. It may not be smooth sailing yet, as we had hoped.

Please let us know in the comments if you have installed BIOS 1.10.1 and your experiences of it. We shall be testing the new BIOS and its effects in the coming days.