@Dankup & @OXiDant I have made a post here DxO PL 7 Painfully Slow to Export JPEGs - #8 by BHAYT where I have included a spreadsheet which shows the results of my tests which do not show the problem you and others seem to be experiencing.
I have included an offer to run tests on my i7-4790K but am only prepared to run two test groups of “problem images”.