Short answer: A Samsung T5 is an affordable choice that’s fast enough for photography, and works with all current Macs and PCs.
The way I like to break it down is that the commonly available connections on current Macs and Windows PCs are:
USB 3 at 5Gbp/s (gigabits per second) — very common, OK for SSDs, especially SATA SSDs.
USB 3 at 10Gb/s — newer, better for NVMe SSDs with up to 1000MBps (megabytes per second) throughput. Personally I think this is the sweet spot for fast, affordable storage for use with Lightroom and Photoshop.
USB 4/Thunderbolt 3 & 4 up to 40Gb/s — uncommon except for Macs, best for pro NVMe SSDs with throughput beyond 2000MB/s. The reason I don’t jump to storage with this expensive protocol is that I don’t think Lightroom and Photoshop will regularly read/write data that fast, but I wouldn’t mind being proved wrong about this.
I find myself staying away from the USB version numbers/names because they are a total mess. Just go by what speed it is.
Samsung T5 is an older SATA SSD, it does up to around 540GB/sec. It’s fine for photos and videos, and costs less.
Samsung T7 is a newer SSD supporting up to 1000GB/sec. Better for frequent large transfers or more demanding uses like a video editing cache drive.
Actual transfer rate can be lower in daily use due to file system overhead, application limitations, cache size, and throttling after the drive starts to get hot. The better reviews of SSDs look at how much they slow down during intensive use as the SSD’s onboard cache fills up and the drive heats up. Maintaining high speed during intensive use is one thing that separates expensive “Pro” SSDs from cheaper ones in the same class.
I totally agree that you have to check the ports on your computer. If your computer has 5Gbps USB 3 ports and you buy a drive capable of 10Gbps, the port will limit the transfer rate to 5Gbps. But the drive’s full speed potential could be realized when you buy a newer computer, or if it’s a desktop and you put in an expansion card supporting a faster USB standard.
Also keep in mind that the protocol (USB 1, 2, 3, 4…) is separate from the connector (USB-A, USB-C…). For example, USB 3 can run through USB-A and USB-C ports, and both USB 3 and Thunderbolt 3 & 4 can run through a USB-C port as they do on Macs.
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