There is no specific order of DQ lanes vs. their fly-by position on the clock. The delays are discovered by the calibration process, and as you noted, used to set up the memory controller. This paper gives a good overview: https://www.nxp.com/docs/en/application-note/AN4466.pdf Summary of the calibrations done: * ZQ (drive strength) calibration * Write leveling * DQS gating * Read DQS delays * Write DQS delays The standard for doing this is laid out in JESD79-3E, available here: https://www.jedec.org/document_search?search_api_views_fulltext=JESD79-3