Here are the basics (QLC is not (yet) on it, it just has one bit more to TLC):
https://www.digitec.ch/de/page/eine-komplexe-angelegenheit-so-funktioniert-eine-ssd-7399
QLC becomes extremely slow when slicing when the fast SLC cache is full.
See Computerbase test:
https://www.computerbase.de/2018-12/samsung-ssd-860-qvo-test/
If you write very little and small bites to the SSD (i.e. mostly read), why not. If you need a normal all-round SSD, then go for the 860EVO.
Is it a laptop or a desktop?
Desktop self-built: suitable screws - often referred to as "SATA screws" - are often included with the enclosure.
Desktop ready-made: when replacing HDD/SSD you can often use the same screws.
Laptop: see "Desktop ready-made
If you need new screws, they are called "M3 screws" (regarding diameter) and the length should be as short as possible. The best way to look for the right screws is to 1) know that you actually need them and 2) know how long they should be.
And: you are not the first to wonder about SSD screws :) https://www.google.com/search?q=ssd+screws+site%3Adigitec.ch
Yes, that should fit. USB 3.1 and 6 or 10GB transfer rate is sufficient. I have an enclosure from UGreen with the same specifications as the ICY Box. I use the hard drive on all my Macs (MacMini and notebooks from 2014). Works flawlessly.
What is your measured throughput rate? USB 3.0 has real throughput rates of about 450 MB/s (and not the promised 625 Mbyte/s = 5 Gbit/s). The transfer rates of the Samsung 860 are also very volatile, depending on whether you are writing, reading or what data type. I would consider anything between 300 and 450/500 MByte/s as "good". All these tests were carried out under laboratory conditions. With the IcyBox, throughput rates of "only" 260 MByte/s are reported. Does the MacBook Pro have USB 3.0 on all USB plugs? Maybe that helps, otherwise get back to me with a few more details.
No, there is not, simply because this is not an external SSD by default like the portable Samsung SSDs. The EVO lacks this security chip which is a prerequisite.
All information about the SSD can be found at the following link: https://www.samsung.com/semiconductor/minisite/ssd/product/consumer/860evo/
There you will also find all the accessories such as software that fits.
The SSD can be installed because hard disks from 7 to 9 mm fit in the T430. The black rubber used in the T430 is available for 7 or 9 mm. The Samsung 860 EVO Basic has a height of 7 mm, so it fits. If 9 mm rubber was used in the T430, the SSD manufacturers also offer small plastic frames that can be screwed on top. If not, simply try to increase the 2mm sideways with something. You won't have any problems once the drive is installed, it will hold in the SATA connector and in these rubber frames.
I don't really see a problem with the hard drive size, because that used to be the case with old Windows versions, but Windows 10 and the T430 motherboard should be able to cope with it.
The maximum is probably about 3700 GB. Since these figures are always calculated with 1000 instead of 1024. Minus any administrative space and any reserve cells.
I took one on Monday for 238 CHF and saw a few days later that the price raised. Thought the same thing as you. Maybe I'll buy a second one tomorrow ;-)
This SSD is actually intended to be installed in a PC and not to be used as external storage. At least without an additional enclosure. So depending on the application, a simple plugged cable to the SSD is short-lived.
If really only a cable then something like this
StarTech USB 3.0 to 2.5" SATA III Adapter
StarTech USB-C to SATA Adapter
Cable with an enclosure doesn't have to be more expensive and bigger though
ICY BOX IB-AC603U3 Adapter Cable, 2.5'' SATA to USB 3.0
i-tec USB-C Advance My Safe Easy (2.5")
or there is the whole still in this kind
LogiLink Quickport
ICY BOX IB-1121-C31