Right now USB C ports are just arriving in laptops and I unfortunately dedicated to go with a cheaper laptop (pc) but with thunderbolt-2.

The thing I don't like about thunderbolt 2 products is the premium price you pay for the Lacie external drives with thunderbolt2. I hope that in the future USB-C devices will come out that will be a bit cheaper as the PC world and mac are seemingly getting 1 standard thunderbolt3 and USB-C.

Long story short will the thunderbolt 2 connection be of ANY use to me in the future world of USB-C on my windows laptop in regards to my normal USB3.0 ports? If yes then what applications of USB-C will it work with?

The only application I really care about is if I could connect an external HD sold with the new USB-C to my Thunderbolt2 via an adapter.

I am thinking I will only get a benefit from thunderbolt 3 devices that are labeled as such to get an adapter to thunderbolt 2 ports for me to get a speed gain compared to USB3.0.

In short the whole idea behind these questions is to have a fast connection between disks and laptop as I am working on big files in Photoshop and TB's of photo's and film ect. Even if USB 3.0 is "fast enough" I would still like to have the Thunderbolt 2 speeds rather then the USB 3.0 speeds.

If it is compatible will the theoretical and effective speed of a USB-C to Thunderbolt2 connection surpass the USB 3.0 max speed?

  • 1
    I have the same question and no one seems to get it. So let me attempt to reiterate the question. I have an old Mac with an old thunderbolt port. I want to plug NEW thunderbolt 3 / USB c devices into my OLD MacBook. I don't care if I can or can not achieve thunderbolt 3 speeds. I know I can't. I expect the newer USB C devices to be more common and less expensive then "Thunderbolt" devices that are expensive and less common.
    – David
    Mar 17, 2017 at 10:15

3 Answers 3


In specific. Thunderbolt can carry USB but USB cannot carry thunderbolt.

In general, as long as your Mac has any Thunderbolt connector, it is highly likely you will be advantaged to connect over thunderbolt instead of using USB. For my money even Thunderbolt 1 is superior in many ways to the best USB 3 chipsets we have today. Now - the above statement is going to be obsolete soon since the newest Thunderbolt 3 chipsets and USB Alternate Mode Functionality mean that USB can be other protocols and TB3 looks to be an awesome step forward for simplifying the need for adapters that you would need on Thunderbolt 2 to get USB 3.0 connectivity today.

  • "Thunderbolt can carry USB but USB cannot carry thunderbolt." . So it means that for me as a PC thunderbolt 2 user if external drives come out I need to have a Thunderbolt 3 devices and not a USB-C devices. My question does USB-C be compatible with thunderbolt 2 will be NO in all cases no ? Even if the only task I ask for data no monitors no power just plain simple data. So if all new devices that have cheap storage are USB-C I will need a USB-C to USB3.0 adaptor. My Thunderbolt 2 port is not going to help me with USB-C products. Apr 21, 2016 at 1:29
  • There are Thunderbolt 2 adapters that run eSATA and USB 3.0 that are quite common. I disagree with the assertion that no help to you if you just need to bring an adapter, but it's clearly not as elegant as Thunderbolt 3 which does Thunderbolt and USB 3 and Displayport and bi-directional power flow (15W out or 100W in).
    – bmike
    Apr 21, 2016 at 13:32

Will there be a USB-C to thunderbolt 2 adaptor?

USB-C is a connector, Thunderbolt is a protocol, which makes this something of a nonsense question. USB-C can carry a number of protocols, including Thunderbolt and USB. Thunderbolt is a protocol used on USB-C and mini-DP connectors, if there are more external connectors than this in common use then I am not aware of it.

There are Thunderbolt mini-DP to Thunderbolt USB-C adapters available. Apple sells one. https://www.apple.com/shop/product/MMEL2AM/A/thunderbolt-3-usb-c-to-thunderbolt-2-adapter This is not an adapter to the USB protocol, any drive connected by this adapter will have to be a Thunderbolt drive to work. Having a USB-C port is not sufficient for this adapter to work, there are many drives that use USB-C but the USB protocol instead of the Thunderbolt protocol.

Thunderbolt drives with USB-C will likely be no faster or slower than Thunderbolt drives with the old mini-DP connector but they are likely to be cheaper. USB-C drives have a bigger market and this will mean lower prices out of economy of scale.

Using a Thunderbolt drive with a mini-DP connector with a computer that supports Thunderbolt on a USB-C port only requires that Apple adapter or something like it. Using a Thunderbolt drive with a USB-C port with a computer that supports Thunderbolt on a mini-DP port means using the same adapter, the adapter is bi-directional. Using a Thunderbolt drive with a captive USB-C cable, a cable that is permanently attached and a USB-C male connector on the end, will not work with that adapter. Or at least not with that adapter alone. Adapters with female USB-C ports do not meet the USB-C spec. They exist, can be purchased, but by not meeting the spec they can damage something. It's best to find the right drive without the captive cable.

I only need data transfer to be higher then USB 3.0

USB 3.0 will allow 5 Gbps, USB 3.1 will allow 10 Gbps. USB 3.0 and USB 3.1 can use the old USB-A and "wide" micro-USB-B connectors that are common on many computers and hard drives, or they can use USB-C. Any USB drive with a USB-C port doesn't make the USB protocol any faster, but it can make them more convenient because USB-C is a nicer connector than the old micro-USB-B.

Getting faster than USB 3.0 with a computer that has a mini-DP Thunderbolt 2 port, and a drive with a USB-C port, means using a Thunderbolt drive and a Thunderbolt mini-DP to USB-C adapter. If the drive does not support the Thunderbolt protocol then it will not work with the Thunderbolt port and adapter. It is possible for an adapter from Thunderbolt 2 on a mini-DP connector to USB 3.1 on a USB-C connector to exist but I haven't seen one. Using a Thunderbolt 2 to PCIe expansion chassis and a PCIe card with USB 3.1 on USB-C ports will also get faster than USB 3.0 with a USB-C drive but that's going to be expensive.

Buyer beware. There are USB-C drives that use the USB protocol, these are limited to USB 3.0 speeds with this computer. There are USB-C drives that use the Thunderbolt protocol, those with the USB-C port can be attached easily. Those with the USB-C captive cable cannot be attached easily. Check the specs before you buy.

A bit of a side note about the future of USB and Thunderbolt... USB 3.2, which is not all that common and may not become common since USB4 came out so soon after USB 3.2, can reach 20 Gbps but only with the USB-C connector. This is the same speed as Thunderbolt 2, half the speed USB4 and Thunderbolt 3. USB4 is a protocol that allows the option to include support for the Thunderbolt protocol, making it backward compatible with Thunderbolt 3 and Thunderbolt 2 but not necessarily reaching the maximum speed of either. The USB4 protocol requires backward compatibility with previous USB versions but this can mean up to USB 3.2 speed, or less than USB 2.0 speed. To claim meeting the USB4 spec requires use of the USB-C connector, but doesn't require offering any higher speed than previous USB versions. Buyer beware again.

Oh, and use the right cable as not all ables are created equal.
A cable tested to meet the USB spec will have the USB icon on it and often a number indicating the speed it was tested to meet in Gbps. No number with the USB icon but with the stylized "SS" symbol usually means 5 Gbps tested speed, it might allow higher speeds, and it might not. A cable that has been tested to meet the Thunderbolt spec will have the Thunderbolt icon on it, this is pass/fail and not different speed tests like USB, the icon means it was tested at the highest data rate. No icon, or not a Thunderbolt or USB icon, does not mean it won't work but does mean it's not tested to meet the spec. A mini-DP cable without the Thunderbolt icon will fit a Thunderbolt 2 port but is not likely to work with any Thunderbolt 2 device. A USB-C cable with no USB or Thunderbolt icon will likely work at some speed, just perhaps not at the maximum speed the computer and device are capable. Buyer beware one more time.


this entire question is backwards... the old connection CANNOT be adapted to by a new one. You can't get an adapter to use USB-C drives on USB or Thunderbolt. You MAY be able to use Thunderbolt 2 on USB-C. USB-C is a faster connection, so you won't be able to shove it into a smaller pipe.


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