Before we make any conclusion of Samsung putting inferior components in some S8 units, please read the following, I think Aamir Siddiqui has written it well enough:
Theoretically speaking, the difference between UFS 2.0 and UFS 2.1 objectively exists and is large enough for phone OEMs to tout the superiority of one over the other.
Practically speaking, most average users and even smartphone enthusiasts will not be able to distinguish between the performance of UFS 2.0 versus UFS 2.1, unless they compare both side-by-side. In real life and daily usage, UFS 2.0 will unlikely be the bottleneck in your flagship experience. Had Samsung gone for eMMC 5.1, the memory specification would have had a much more profound and noticeable impact on your experience. Thus as a silver lining, Samsung is only juggling between UFS 2.0 and UFS 2.1 for now.
For the information we have gathered so far, we have come to the following conclusion, if anyone has any finding that differs from this please let us know and show us the screenshot:
Samsung UFS 2.1:
All Exynos Models -> S8 / S8+
Toshiba UFS 2.1:
Snapdragon Model -> S8+ ONLY.
Toshiba UFS 2.0:
Snapdragon Model -> S8 ONLY.
Interesting fact: on their website, Samsung used to list S8/S8+ with UFS 2.1 flash storage, however now they have changed the specs and listing only UFS without specifying whether its 2.0 or 2.1.
See below screenshots of Samsung official website, I took the first screenshot 1 week ago and the 2nd today. Samsung has silently removed the UFS 2.1 line.
Now we know that some S8s are using ufs 2.1 chips while others using ufs 2.0 only.
Luckily there's a way to exactly identify your flash chip.
Download any terminal emulator from play store.
for example this one will work
then type in this in the terminal window:
what I circled in red is the ufs model number:
In this case get:
KLUCG4J1ED - B0C1
Now what I heard is that all exynos variants of S8 and S8+ uses UFS 2.1, all Snapdragon S8+ also uses UFS 2.1, and only some Snapdragon S8 uses UFS 2.0.
You may also get something like:
Alternatively you can use Androbench to test the speed of your flash chip. For the sequential read speed, I believe that S8 with UFS 2.0 usually fall in 500MB/s range, while those with UFS 2.1 can get close to 800MB/s. However keep in mind that this is not the accurate way to go, if you really want the truth, pls use terminal and the code.
For example results from my UFS 2.1 S8:
Please test your own S8 and let us know what you get.