Dell may not have fully fixed the DPC latency issues that have been affecting the XPS 15 9570, but it has promised to have eliminated them from its successor, the XPS 15 7590. Deferred Procedure Call (DPC), for those who have not read our previous articles, allows drivers to execute tasks and helps a system process these requests based on their importance. Buggy, or poorly written, buggy drivers can make numerous DPC instructions, which eats up resources and makes it difficult for a system to prioritise important tasks. One of the main culprits for the XPS 15 9570 has been ACPI.sys, which has caused audio stutters and glitches when playing or mixing music.
Dell reduced latency times with the release of BIOS 1.10.1 for its flagship 15.6-inch laptop, although it is yet to eliminate latency spikes as we reported a few weeks ago. Now, Frank Azor has promised that the upcoming XPS 15 7590 will not share the same DPC latency issues that its predecessor has. In replying to a question about whether the new XPS 15 would ship with this issue, he stated the following:
Only some of the mechanical assembly is the same which has no affect on DPC latency. DPC latency sensitivity is part of all of our designs and validation moving forward since the last set of escalations.
— Frank Azor (@AzorFrank) June 4, 2019
According to that statement, the XPS 15 7590 only shares its outer shell with the XPS 15 9570 and Dell has refreshed all internal components. We shall reserve judgment until we have gotten our hands on the refreshed XPS 15, but it is interesting to note that Dell has built additional DPC latency checks into its hardware validation processes. Hopefully, that has eliminated the issues from occurring on the XPS 15 7590, but Dell still needs to do the same with the XPS 15 9570.