Is it safe to use USB 2.0 to 3.0 adapter cables?

Using that adapter is safe, but just so you know, USB always defaults to the lowest speed. So while you can use this adapter without worries, it won’t magically boost speeds or charging. If you’d like to get the benefits of USB 3.0, a PCIe USB 3.0 card isn’t too pricey if you can spare the lanes.

For sure, it’s safe! Keep in mind the connection will only operate like a USB 2.0 socket. If you hook up a device that supports USB 3.0, it won’t be any faster than that 2.0 speed.

Yeah, it’s totally safe to use! Just a heads-up though, your ports will only operate at USB 2.0 speeds, but it should work just fine. If you really want to take advantage of USB 3.0 speeds, consider getting a PCIe card with a 3.0 header if you have a spare slot.

Absolutely, it’s perfectly fine. Just remember that USB is designed to be backwards compatible, so your setup will just run at those slower 2.0 speeds.