Samsung T7 read write speeds

According to Samsung, the T7 Shield has a USB 3.2 Gen 2 (10 Gbps) interface, not a Thunderbolt one.

https://semiconductor.samsung.com/consumer-storage/portable-ssd/t7-shield/

I believe that the USB-C ports on the 2018 Mac Mini and on the M1 MacBook Air both are supposed to support USB 3.1 Gen 2, a.k.a. USB 3.2 Gen 2x1, a.k.a. "USB 3.2 Gen 2 (10 Gbps)." They are not using the same circuitry and software to implement that mode, so I could see there being some performance difference.

It does seem strange that the performance difference would be that large and that the M1 MacBook Air would be trailing the i7 Mini (rather than the other way around).

RE: "n fact, due to the chip architecture, the M1 will get faster external SSD speeds with most external drives than the M2 machines will because the M1 is equipped with 2 NAND chips and the M2 only has one."

1. The number of NAND flash chips making up an Apple Silicon Mac's internal SSD has no bearing on the performance of that Mac's external SSDs. The 9to5Mac article to which you linked concerns the speed of USB data transfer over an Apple Silicon Mac's USB-C (Thunderbolt) ports. The fact that the ports support Thunderbolt is incidental, since the transfers used USB protocol. The speed of the internal SSD seems to have been immaterial here, since the tests appeared to involve just writing and reading to the external SSD (and not copying files to or from the internal SSD).
2. It has been reported that M2 Macs with 256 GB internal SSDs have much lower SSD performance than M2 Macs with 512+ GB SSDs or than M1 Macs. The reason is a reduction in the number of NAND flash chips – from (2 x 128 GB) to (1 x 256 GB) - which precludes the possibility for parallel reads and writes.
3. There are similar reports about 14"/16" M2 Pro/Max MBPs that have only 512 GB of internal SSD storage. In this case, we're talking about 2 NAND flash chips versus 4 NAND flash chips, so even the 'slow' 512 GB SSD delivers performance on a par with what you might expect from a Thunderbolt 3 / M.2 PCIe NVMe SSD.
4. Even a M2 MacBook Air with 256 GB of SSD storage, on one NAND flash chip, turned in a write performance of 1598.6 MB/s and a read performance of 1560.9 MB/s. USB 3.1 Gen 2 has a speed of "up to 10 Gbps (1250 MB/s)" before overhead. So even the 'slow' 256 GB M2 MacBook Air SSD (which is slow by the standards of Thunderbolt 3 SSDs and other modern internal Mac SSDs) is faster than your Samsung T7 is … is faster than your Samsung T7 could be if it was connected to a perfect USB-C (USB 3.1 Gen 2) port!

https://www.macrumors.com/2023/01/24/m2-mac-mini-256gb-slower-ssd/

https://9to5mac.com/2023/01/24/macbook-pro-ssd-performance-drop/

https://9to5mac.com/2022/08/04/macbook-air-m2-vs-m1/

RE: "Simply, the USB support on the MacBook Air USB 3.1 gen 2 single lane. The T7 supports USB 3.2 get 2 at 10 Gbps with two lanes."

So you're saying that Samsung's "USB 3.2 Gen 2 (10 Gbps)" specification translates to "USB 3.2 Gen 1x2" (which has no USB-IF marketing name) rather than to USB 3.2 Gen 2x1 (a.k.a. USB 3.1 Gen 2 a.k.a. USB 10 Gbps)? If we assume that this is the case (the lane speed is 5 Gb/s or 625 MB/s) and that the 2018 Mac Mini is negotiating the transfer down to a single lane, how would the Mini achieve a transfer rate of 650 MB/s to the SSD?

You're right that the USB specs can be "a ball of confusion". USB4 has three "up to 20 Gbps" USB data transfer modes. One of them is USB 3.2 Gen 2x2 ("up to 20 Gbps"). There are a couple of new, incompatible USB4 modes … one of which has a marketing name, one of which doesn't. Naturally, USB4 20 Gbps mode is mandatory for USB4 host ports, while USB 3.2 Gen 2x2 mode is optional for them.

People in other forums have reported that Apple Silicon Macs do not support USB 3.2 Gen 2x2. If you hook up a USB Gen 2x2 SSD (there are one or two of those) to an Apple Silicon Mac, things will fall back to "up to 10 Gbps" speed. To be fair, Apple doesn't claim that Apple Silicon Macs support USB 3.2 Gen 2x2, but given that they DO support the optional "up to 40 Gbps" Thunderbolt and USB4 40 Gbps modes, one might be forgiven for thinking that they supported all lesser USB speeds, as well.

Oh, and all of the USB4 Gen 2x(whatever) modes are different from their USB 3.2 Gen 2x(whatever) counterparts. Within USB 3.*, if you matched the Generation and the number of Lanes, you were talking about the same protocol whether it was called, say, USB 3.2 Gen 1x1, USB 3.1 Gen 1, or USB 3.0.

https://en.wikipedia.org/wiki/USB4

All of the 2011 MacBook Pros have USB 2.0 – which has a theoretical maximum speed of 480 Mb/s (60 MB/s), but tends to deliver speeds more like 30 MB/s – 40 MB/s in practice.

That explains why the 2011 MBP delivered only 45 MB/s. Even the USB-A (USB 3.0) ports on the 2018 Mini, while incapable of the 950 MB/s of the same machine's USB-C(USB 3.1 Gen 2) ports, would blow 45 MB/s away.

Simply, the USB support on the MacBook Air USB 3.1 gen 2 single lane. The T7 supports USB 3.2 get 2 at 10 Gbps with two lanes. So connecting to the MacBook Air, you are only essentially getting 5 Gbps. which is close to the number you are getting.

All the new USB specs are a ball of confusion and almost seem to be made to be for drive manufacturers to tout high speeds on all devices when it simply is not true.

USB-C generally in the 950-1000 MBps

USB-A generally about half that

RE: "All the new USB specs are a ball of confusion and almost seem to be made to be for drive manufacturers to tout high speeds on all devices when it simply is not true."

How about when USB 2.0 came out? "USB 2.0 Full Speed" very likely sounded like "up to 480 Mbps" to the average computer buyer. But it really meant "up to 12 Mbps" (one of the USB 1.* speeds). To get "up to 480 Mbps", you had look for devices specified as supporting "USB 2.0 High Speed."

They are also the designation of USB type:

See??