[newaccount74]

On the Mac, there's a simple way to check cables:

Take a USB3 device, plug it in with the cable, and then go to System Profiler (Apple Menu -> About this Mac -> System Profiler). Look for the device, and check the speed. If it says 480MB/s it's a USB 2 cable, if it says 5GB/s, 10GB/s or 20GB/s then it's a USB3 cable.

I assume there's a way to do the same thing on Windows and Linux.

[hanche]

I just tested that, and it works. Using a Samsung T7 SSD. Clever. Now I wonder if a similar trick works for power capabilities?

[newaccount74]

Coconut battery shows how much power your battery is charging with. I've only used this to compare power supplies, but I don't see why it shouldn't work with cables as well. Of course that only works when the battery is empty enough to actually fast charge.

[voltagex_]

There's $50-200USD USB PD meters on AliExpress. I like Ruideng / RD-Tech brand ones.