Difference between USB 3 & Thunderbolt

[Howard Brazee]

The 24" M1 iMac I've ordered has 4 ports:

• Two Thunderbolt / USB 4 ports
• Two USB 3 ports

My assumption is that the USB 3 ports are there because they're cheaper to make than Thunderbolt ports.

I don't have any Thunderbolt accessories, nor even a Thunderbolt cable. (Well I have Thunderbolt 1 to HDMI cables, but they don't count).

Until I get a Thunderbolt device and cable, is there any reason to prefer one port over another for my connectivity?

 

[Cory Cooper]

Hi,

Thunderbolt (Thunderbolt 3) / USB 4 - can connect Thunderbolt or USB devices
USB 3 - Can only connect USB devices

Both use the USB-C connection type and have USB 3.2/2.0 backwards capability.

C

 

[Howard Brazee]

Which is why I inferred that Thunderbolt ports must be more expensive to make. Otherwise, just make them all Thunderbolt.

So there is no reason for me to pay attention at all which port to use until I someday get a Thunderbolt device (and cable).

 

[Cory Cooper]

Yes, they are more expensive, since Thunderbolt is an "active" technology that have some circuitry in the ports, cabling, and peripherals.

Yes, use the USB ports first for USB devices, then you can use the Thunderbolt/USB ports for USB devices until you purchase some Thunderbolt devices.

C

 

[EdSinger]

I have always been led to believe that Thunderbolt devices can be daisy-chained - i.e. connected in series, in which case no need for more than two ports on any device. Is this incorrect?

 

[Howard Brazee]

Thunderbolt devices can be daisy-chained, but not every device is built that way. If they were, theoretically, you would only need one port. I want my hub to be Thunderbolt for future expansion though. My devices, such as my iPad and my iPhone, my memory card, and my two HDMI ports (I run karaoke) are USB.

I want more power though. This morning, I woke my M1 iMac to discover six copies of “A Bunch or “Disk Not Ejected Properly Eject “LaCie SSD” before disconnecting or turning off and one copy of “USB ACCESSORIES DISABLED Unplug the accessory using too much power to re-enable USB devices." windows—iPad Pro is spinning in FInder, “Syncing Podcasts (Step 4 of 4)—Finder shows LaCie SSD connected.”.— I suspect an issue is that the USB-C and Thunderbolt ports on my M1 iMac don't have enough power.

 

[EdSinger]

« Thunderbolt devices can be daisy-chained, but not every device is built that way »

In which case I would say they are not thunderbolt devices but are usb-3. Same plugs and sockets but different devices.