Internal Hard Drives vs External Enclosure

Its looking like external is going to have to be the solution for now. Looking at the measurements of those cases, the enclosure in my desk that holds the computer is not tall enough or deep enough. I don't want to replace the desk now, so I'm thinking that an external housing will let me get new, faster, higher capacity drives leaving only 1 inside my case for less clutter inside, and the enclosure will fit on the top of my desk.

But that brings up a new question. The enclosures have both eSATA and USB3. Which would be better performance to interface with my computer? If I want to go with eSATA I will have to buy an adapter (because my motherboard doesn't have eSATA) like there is one that is an eSATA receptacle on an expansion plate that goes in the back of the computer and an internal SATA cable runs from that over to my board's SATA connection. Is the performance gain worth spending $20 on that, or better with USB3?

As for interfaces, your USB 3.2 gen2 (aka USB 3.1 gen2) (1212 MB/s) (*) is superior to SATA3 and eSATA3 (600 MB/s). Imo your best SATA3 option is internal, despite the "clutter".

(*) Bear in mind that the "gen2" part is important, as USB 3.2 gen1 = USB 3.1 gen1 = USB 3.0 is a lower standard at 500 MB/s. In practice there isn't a lot of difference among the three in many situations, see below.

The said speeds are the physical ones that account for the raw electrical speed (that is higher) and the 8b/10b or 128b/132b hw encoding (that lowers it a bit). No USB or SATA transmission can physically surpass the said rates in MB/s for every standard.

Protocols have overhead that use a bit of the bandwidth, although the concrete amount isn't an exact number. According to USB 3.0 - Wikipedia the specification considers it reasonable to achieve 3.2 Gbit/s (400 MB/s) or more in practice. I use USB 3.0 myself but I haven't used yet fast enough devices that could achieve 400 MB/s. If adequate, it would be a lot better than with USB2, which physically can reach 60 MB/s (exact number w/o protocol overhead) but in practice it hardly surpasses half of it (30 MB/s).

So we end up with a theoretical max of about 1 GB/s that USB 3.2 gen2 drives may promise. Using SATA3 or gen1/USB3.0 drives would about halve that, but in practice it wouldn't be a lot lower performance, except if you search for sequential speeds (for example, image backups) and have fast devices in practice.

- Not all drives have the highest specification that its connection standard allows.

- Sequential vs random read/writes: the max speed specification applies the most to sequential reads w/o thermal throttling. Random reads/writes speeds are lower and quite equal among all serious solid state drives (gen1, SATA3 or gen2). See for instance this video https://www.youtube.com/watch?v=V3AMz-xZ2VM .

- Sustainable write speed: applies to sequential writes done to devices that have fast (SLC) and slow (TLC) write speed sections, usually the fast quite smaller (or very small in some cases) although it can still serve not very large writes at the maximum specified speed. When any write is done, the firmware directs it to the fast section unless it's 100% used, then the write will be done to the slow section. The write speed of the slow section is the "sustainable write speed", that's the max speed in practice of writes large enough to fill up the fast section (in my SATA3 SSDs with about 500 MB/s max, it's about 200 MB/s). When idle, the firmware will free up the fast section transferring its contents to the slow one, until a new read or write is done which will always have preference. Reads can be done from either section at about the same speed.

- Thermal throttling: applies to reads or writes large enough to rise the device temperature. External devices will heat up more in general.

This review is ancient but teaches a lot. I'd also read the comments.
Seagate Fast SSD and SanDisk Extreme Portable SSD 1TB USB 3.1 DAS Review

You brought up a good point about the type A and type C. Many of the boxes use 3.1 Gen 1. This particular one has 3.2 Gen 2 Type C so it should in theory be the fastest one. I have 1 type C port on my IO panel.

Mediasonic USB 3.1 4 Bay 3.5''' SATA Hard Drive Enclosure - USB 3.1 Gen 2 10Gbps USB Type C (HF7-SU31C) - Newegg.com