I had a MacBook Air mid-2013 that took about 11 seconds to boot to the login screen on Sierra. After changing to High Sierra through an upgrade and clean install, booting to the login screen takes about 25 seconds using the original Apple Sandisk ssd. On my mid-2013 13" MacBook Pro, there was no change in boot times.
Anyone notice that the os boots faster or slower with an nvme drive?
I am new to you. I have checked my MacBook Air 13 Mid2013 with MZ-JPV256 (samsung, Apple genuine AHCI SSD), It is OK, no delay. I looked for related information.
High Sierra slow booting
https://forums.developer.apple.com/thread/80615
What's your boot time after upgrade to High Sierra?? Mine is 28s.
https://www.reddit.com/r/MacOS/comments/737vl5/whats_your_boot_time_after_upgrade_to_high_sierra/
MBP extremely slow after SSD Upgrade. What's wrong with my mac?
https://www.ifixit.com/Answers/View/168245/MBP+extremely+slow+after+SSD+Upgrade.+What's+wrong+with+my+mac
1 "slow booting" is found High sierra beta, jun 2017. It has been 4 months elapsed, but has not been solved.
2 It doesn't depend on Mac's model (even MBPr 15 2015, 2016, MBPr 13 2015), our no-detecting model contained.
3 It also occurs in Apple genuine AHCI SSD, not limited to NVMe SSD, even SATA SSD.
4 It is pointed out that it is related to Trim or APFS. Windows boot normally.
5 There is a case that Although replacing the SSD was ineffective, it was solved by replacing the SATA cable.
These informations will not be a direct solution to us, But we should check the contact of the connector(s) again.
postscript 2017/10/30 14:00
I have checked also my MacBook Air 13 Mid2013 with MZ-HPU256 (samsung, AHCI SSD), It was OK, no delay. but TRIM was not ON as installed, So using trimforce command on Terminal, set TRIM ON. The result was still OK, no delay.
MacBook Air 13 Mid2013 with MZ-HPU256 with sintech small (or old) adapter (Corrected) High Sierra
Boot or re-Boot issue : No
Boot delay : No
Sleep (wake-up) issue: Yes, with hibernatemode 0 standby 0 autopoweroff 0 : OK (tentative)