Interesting stuff.
Unformatted (over provisioning) is critical in my experience too. I've been using Sammy since 840 pro. Still using a couple 850 evo in an older PC, and currently using pretty heavily used 860 evo's in my current PC. I take over provisioning to the next level on my boot drive and allocate a full 25%. Over kill? I honestly don't know, but for a drive that has had three years of daily heavy use, it still runs as well in AS SSD, various ATTO runs, and Crystal Bench. Crystal disk Info shows 89% remaining life. My other 860 evo''s (a 2TB gaming drive etc etc) are all still at 99%. I OP them at between 12% to 15%.
I wonder if it's because at least up to the 860 Samsung used the 3 level or layer?, MLC Nand? (That off the top of my head, apologies terminology sucks, but you know what I mean.)
What I didn't know is that now a days OP partition is added as a hidden extra partition.
But it makes sense. My newest, and cheapest drive is a Trancend TS2TSSD220Q 2GB. Treated with the same care and love as my Sammys get, but it just can't compete in terms of typical usage. It's already at 99%, and I've barely used it. It uses the newer but cheaper 4 layer or level QLC Nand (Off the top of my head). My mistake.
It has been relegated to 2nd backup drive, as even running ATTO sequential read/write tests with the test file set to 512MB (default is 256MB) it rapidly drops write speeds from exepected 515 MB/s range max to as low as 10MB/s. All over the place. These runs are at the default "direct I/O." So it clearly relies on some caching excessively. Is huge reliance on caching the "new thing," for newer but cheaper SSDs??
I stop there with the technical aspects as I know the folks on here are genereally a step, and some leaps and bounds above my (fill in space) tech knowledge.
I'll finish by simply saying NONE of the poor performance issues/degredation have ever occured on any of my Samsung 840, 850, 860 SATA3 SSDs. Additionally they all have far more wear and tear on them.