Thanks for the info! I was going off your post above with info from another member.You should have NO issues with sleep or hibernate in a 2015 iMac as its bootrom is already patched to work with all NVMes. If in any case you are having issues you disable hibernate (and its triggers standby and autopoweroff), the Mac will sleep and wake normally. For reference here.
Blade drive upgrade by ssdaytona
Device: late 2015 5K
SSD upgrade: 24GB Blade -> 512GB Samsung 970 Pro NVMe SSD
Speed test: 2930 MB/s read, 2170 MB/s write
OS: OS X
Adapter: Sintech ST-NGFF2013 and ST-NGFF2013-C
Issues after fresh OS install: sleep issues with both adapters, have to disable sleep
Nice job on your upgrades! I’ve always installed the OWC thermal sensors but will be great if we can confirm that’s no longer required for all iMac models after newer firmware updates (or at least true for non optical drive iMacs models)
Having said that I now remember someone else mentioning not needing the thermal sensor with a 27 iMac years ago which I believe was also 2013. I’ll have to search for the post, maybe that model is a strange exception. I’ll do some testing myself when possible and will report back.