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Frequently Asked Questions (FAQs) about the Thunderbolt port on a Dell PC

Summary: This article is a collection of answers to the most frequently asked questions about the Thunderbolt ports and connectors on Dell equipment.

This article may have been automatically translated. If you have any feedback regarding its quality, please let us know using the form at the bottom of this page.

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Table of Contents:

  1. Introduction
  2. Frequently Asked Questions



SLN300756_en_US__1Thunderbolt-logo2 SLN300756_en_US__2Thunderbolt-logo3

This article provides a reference on Thunderbolt ports on a Dell PC, by going over the most frequently asked questions (FAQs) by our end users and providing clear answers to each.

The questions vary from what the ports look like to how to troubleshoot them when something goes wrong.

I hope you find what you need below. If not, contact your local support.

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Frequently Asked Questions


What is a Thunderbolt port and What does it do?

A Port or Connector: A Port or Connector on a Dell PC has either holes or a slot that matches the plug or device that you are connecting to the Port.
Thunderbolt (Previously Light Peak): Was jointly developed by Intel and Apple and is available since Feb 2011 and is an industry standard that defines the cables, connectors and the communications protocols used in a bus. These are used for connection, communication and power supply between computers and electronic devices.
Note: Thunderbolt was conceived as an optical technology and was intended to run exclusively on optical fibre cable and use an Optical Physical Layer. It was discovered that copper was cheaper and still provided the high speeds that were required. It is still tied into the PCIe signal and is ideal for 4K graphics.

How does it work?

Thunderbolt is a revolutionary I/O technology that supports high-resolution displays and high-performance data devices through a single, compact port. Thunderbolt is a hardware interface that allows for the connection of external peripherals to a computer. It uses the same connector as Mini DisplayPort (MDP). Thunderbolt combines PCI Express (PCIe) and DisplayPort (DP) into one serial signal alongside a DC connection for electric power, transmitted over one cable. Up to six (6) peripherals may be supported by one connector through various topologies.

SLN300756_en_US__4Thunderbolt process

Thunderbolt supports Data, Video, Audio and Power from a single port.

Thunderbolt cables are mainly copper. (There are still some fibre optic cables available, but power cannot be transmitted through them.) The cables are bi-directional and each Thunderbolt port supports two channels, which means the port can send and receive data at the same time. It can also supply power through to any peripherals plugged to that port. There is a limit of six (6) devices plugged in a daisy chain to any one (1) Thunderbolt port. These are Active cables, so they tend to cost more than similar cables for Display Port and USB.


Thunderbolt 3 came out in 2015 and moved from a Mini DisplayPort connector to a USB Type-C connector and incorporated a number of advances over Thunderbolt and Thunderbolt 2. Whilst there was limited adoption of the standard while it used the Mini DisplayPort connector, this changed with the inclusion of the Type-C connector to the Thunderbolt Interface.

SLN300756_en_US__6TB3 usage

2020 brought us a new standard from Intel named Thunderbolt 4. Thunderbolt is a high-speed protocol. It can dynamically adjust data and video bandwidth. It is now the basis of the USB4 protocol specification. Thunderbolt 4 and USB4 products use the same protocol specification which improves compatibility for any USB Type-C based products.

Intel Thunderbolt comparison chart

What types of Thunderbolt port are in common use?

There are currently four (4) types of Thunderbolt ports in use. Select your version from the tabs below to see the available ports and plugs and what they can do :


Thunderbolt 1 was the first revision of the Thunderbolt port that was brought out in 2011.

It has data rates of 10 Gbit/s and is dual channel.

Port SLN300756_en_US__7Thunderbolt_Port Plug SLN300756_en_US__8Thunderbolt mini display port

Thunderbolt 2

Thunderbolt 2.0 is an update on the original Thunderbolt specification that came out in 2013.

It increased the signaling rate from 2 bi-directional 10 Gbit/s channels to a single bi-directional 20 Gbit/s channel. The amount of data able to go through the connection hasn't increased, but the throughput of a single channel has doubled.

Thunderbolt 2 can both stream 4K video and write it to Hard Disk at the same time.

The connector is still Mini Display Port and Thunderbolt 2 supports the latest DisplayPort 2.1 specification and is backwards compatible with Thunderbolt 1 devices. These legacy devices still only work at Thunderbolt 1 speeds.

Port SLN300756_en_US__7Thunderbolt_Port Plug SLN300756_en_US__11Thunderbolt mini display port

Thunderbolt 3

2015 brought us Thunderbolt 3 which improved upon Thunderbolt 2 and uses a USB Type-C Connector.

Transfer speeds were doubled from 20 Gbit/s to 40 Gbit/s, which gives 4 times the data and twice the video bandwidth of any previous cable.

It supports at minimum 1 x 4K display at 60 Hz and increases charging to 100 Watts for a 15 W device.

As with previous standards, it incorporates support for USB 3.1, so that regular USB type-C cables can also be used in this port.

As it incorporates a new connector, it is not compatible with legacy devices, without the use of intermediary adapters.

Port SLN300756_en_US__13Thunderbolt3_Port Plug SLN300756_en_US__14Thunderbolt connector type-c
SLN300756_en_US__15Thunderbolt performance2

Thunderbolt 4

Thunderbolt 4 is new out in 2020 and continues to use a USB Type-C Connector.

Transfer speeds remain 40 Gbit/s, which still gives 4 times the data and twice the video bandwidth of any previous cable.

It supports at minimum 2 x 4K, or 1 x 8K display at 60 Hz and increases charging to 100 Watts for a 15 W device.

Where Thunderbolt 3 supports only 16 Gbit/s data rate via PCI express, Thunderbolt 4 supports double that at 32 Gbit/s.

As with previous standards, it incorporates support for USB4 and older, so that regular USB type-C cables can also be used in this port.

It is still not compatible with legacy devices, without the use of intermediary adapters.

Port Type-C Port Plug Type-C Connector
Intel Thunderbolt Speed Comparison
Intel Thunderbolt Port Comparison
Intel Thunderbolt Cable Comparison

Does Dell supply Thunderbolt adapter cables?

Dell has a number of adapter cables available for sale on their online Store:

Dell Adapters

Type Appearance
Dell Adapter - USB-C to HDMI SLN300756_en_US__17Dell_USB-CtoHDMI_BK
Dell Adapter - USB-C to VGA SLN300756_en_US__18Dell_USB-CtoVGA_BK
Dell Adapter - USB-C to Ethernet (PXE Boot) SLN300756_en_US__19Dell_USB-CtoEthernet_BK
Dell Adapter - USB-C to USB-A 3.1 SLN300756_en_US__20Dell_USB-CtoUSB-A3-0_BK
Dell Adapter - USB-C to HDMI/VGA/Ethernet/USB 3.0 SLN300756_en_US__21Dell_USB-CtoHDMI-VGA-Ethernet-USB3-0_BK

VisionTek Adapters

Type Appearance
VisionTek - USB Type-C to Display Port SLN300756_en_US__22VisionTek_USB-CtoDPort_BK
VisionTek - USB Type-C to HDMI SLN300756_en_US__23VisionTek_USB-CtoHDMI_BK
VisionTek - USB Type-C to VGA SLN300756_en_US__24VisionTek_USB-CtoVGA_BK

C2G Adapters

Type Appearance
C2G - USB (2.0) Type-C to USB-Micro B USB SLN300756_en_US__25C2G_USB-2-0CtoUSB-Micro_BK
C2G - USB (3.1) Type-C to USB Micro B USB SLN300756_en_US__26C2G_USB-CtoUSB-Micro_BK


What Operating Systems support Thunderbolt ports?

So far there has not been an operating system that has not supported Thunderbolt. Everything from Apple, Linux, and Windows use this standard as long as the technology and drivers are available.

What does it mean, when the reference material says the Thunderbolt is powered?

From the beginning we have seen that some external devices do not supply their own power and need to take power from the PC they are connected to as well as transfer data across the same connection :

Mini Display Port
Mini Display Port supplies 10 Watts charging.
Type-C can supply 100 Watts of power charging for a 15W device.
Powered from the PC

These devices are hot pluggable. That means they work as soon as they are plugged in. However, some proprietary drivers may be needed for any addon functions the devices may have.

Cable Adaptors (Various Ports)


Cable Adaptors are basically port adapters. They take the Thunderbolt port from your PC and convert it to any of a number of other port types. Taking into account the bi-directionality some can go to two separate ports, such as eSATA and SuperSpeed USB 3.0 in the example above.

If a cable adaptor does not work - test it outside of the operating system and in other Thunderbolt ports.

You can also test it on another system to see if the issue follows the cable.

Device Hub (Various Ports)


There are powered hubs and unpowered hubs, but hubs at their base are a cheap and easy way of expanding how many devices you plug up to a PC from a single port.

One (1) plug from the Hub goes to your PC and allows a number of devices to connect to the ports on the Hub and pass through to the PC.

Powered Hubs work better than unpowered ones do, but with Thunderbolt powered hubs are hard to distinguish with cabled Docking stations.

You can gang a maximum of six (6) devices.

If you are having trouble with a hub, try different combinations of ports and devices and try on another PC.

Remember 1 connection always has to go to the PC.

Testing in other Thunderbolt ports and on another system identify where a fault originates.

With Thunderbolt you get the added feature that the ports on the Hub can be of various different types.

Expansion Card (Various PCIe)


Expansion cards can increase the number of Thunderbolt ports on your PC as they also tie into the PCIe socket.

If you have issues using the device then try the device in several ports and systems to see where the fault follow.

Audio Interface


Thunderbolt Audio Interfaces offer a super-fast 10Gbps connection allowing a much quicker data transfer rate in comparison to that of USB or Firewire. This technology offers ultra-low latency performance for the recording and playback of audio. Thunderbolt also allows the connection of multiple devices such as hard drives and HDMI/USB 3/USB4 hubs all without sacrificing performance or speed.

Testing in different ports and on another machine identify where a fault originates.

Thumb Drives


Flash/Thumb Drives are usually low power storage devices and have taken the place of the floppy disk.

Not all drives are compatible with all Thunderbolt ports. You may have a conflict between the port and the drive manufacturer.

Try the device in several ports and systems to see where the fault follows.

Passport Drives


Passport Drives are usually low power storage devices and have taken the place of the floppy disk. They tend to be under 2TB in size and are most often used as expanded storage for mobile devices.

Not all drives are compatible with all Thunderbolt ports. You may have a conflict between the port and the drive manufacturer.

Try the device in several ports and systems to see where the fault follows.

Video Capture Devices


Video Capture Devices are usually low power devices that connect to your PC and capture your screen contents in HD quality. They tend not to store the video on the device but on the connected PC or on an expandable device plugged to the PC.

You may have a conflict between the port and the drive manufacturer.

Try the device in several ports and systems to see where the fault follows.

Independent Power Source

Tablets / Smartphone's


Both Tablets and Smartphones have their own Power supply but can take power from the PC as well. They are commonly used either as remote devices or as added storage in conjunction with a PC.

External HDD and SSD

SLN300756_en_US__35Thunderbolt_Hard_Drive_BK_01 SLN300756_en_US__36Thunderbolt_External_SSD_BK_01

Both HDD and SSD external drives usually use an external Power supply for long term use. Some passport drives take power from the PC for the short term uses. Thunderbolt offers transfer speeds in excess of those possible by USB 3.1/USB4, Firewire and eSATA. With Thunderbolt 3 and 4, these speeds are only limited by the limits of the hardware devices themselves.

External RAID Storage


Both Offline and Network Attached Storage use their own external power source and are often configured as RAID to help with either write speeds or failover cover in case of disk failure. Striped helps write speeds and Mirrored helps failsafe against data loss. Thunderbolt offers transfer speeds in excess of those possible by USB 3.1/USB4, Firewire and eSATA.

External Media Server


These devices come with their own external power source and work much as the Network Attached Storage does. Thunderbolt cables supply Video, Audio, Data and Power at high rates and supports 4K streaming.

Monitor Displays (4K and higher)


Thunderbolt started out as an Optical Standard and is still ideal for video playback. Thunderbolt 3 and 4 can support two monitors on 4K at 60Hz.

Digital Camera and Video Equipment

SLN300756_en_US__40Thunderbolt_Camera_Equipement_BK_01 SLN300756_en_US__41Thunderbolt_Cinema_Camera_BK_01

These devices come with their own internal battery and some form of extra cabling to plug up to mains power to charge after use. These devices are designed to work with Thunderbolt to capture 4K footage straight to your PC or Storage Devices.

External Video Editing Suite


These devices come with their own external power source utilize the speed and quality of Thunderbolt to quickly create high-quality 4K videos and images.


External Wired Dock


These devices come with their own external power source and are used to expand the PCs options. They can include Optical Drives, Hard Drives, but mostly they are expanded versions of the Hubs which allow for multiple devices and screens to work with your PC. Many manufacturers offer these docks as Desktop Workstations as the Thunderbolt connection means they work with any PC with a Thunderbolt port. The Dock shown here is the Dell Thunderbolt Wired Dock and works with non-Dell systems that have a Thunderbolt port.

Top View



1 Power Button    
Front and Right Hand Side View



1 Audio In/Out Connector 2 USB 3.1 Connector
3 USB 3.1 Connector 4 Power LED
5 Security Lock Slot    
Left Hand Side View



1 Dell Proprietary 56 Pin Connector    
Note: There are two proprietary cables for use with the connector on the left-hand side of the dock. The first is a 56 pin connector going to a Thunderbolt 3 or 4 USB Type-C connector for use when paired with a Thunderbolt Device. The second is a 56 pin connector going to a USB Type-C connector using the DisplayPort standard for use with a non-Thunderbolt 3 or 4 device. You can source these Cables from Dell.
Rear View



1 HDMI Connector 2 VGA
3 Gigabit Ethernet Connector (NIC) 4 USB 3.1 Connector
5 Stereo Out Connector 6 Mini DisplayPort Connector
7 DisplayPort Connector 8 USB 2.0 Connector x2
9 Thunderbolt 3 and 4 Type-C Connector 10 AC Power Connector

How do I identify a working Thunderbolt port in a Windows operating system?

Your Thunderbolt ports on your Dell computer are plug and play. If you have issues with your Thunderbolt port, it is port related, driver related or device related. The following solutions help you identify the problem to resolve your Thunderbolt port issues.

Begin troubleshooting your Thunderbolt ports by checking Device Manager to see if your Thunderbolt ports or hubs are working properly.

  1. Click the Start button.

Note: In Windows 8, move the mouse cursor to the upper right corner of the screen until the Charms Bar appears, and then click Search. In the search box type Control Panel.

In Windows 10, click or tap on the Windows Start button and type Control Panel.

  1. Click Control Panel.

  2. Click Hardware and Sound.

  3. Click Device Manager.

  4. Double-click Chipset and check under the PCI Express Root to see if all your Thunderbolt connections are functioning correctly. Any devices not functioning have a yellow exclamation mark in front of them.

  5. If Device Manager shows any Thunderbolt connections are not functioning, check for updated drivers.

  6. If the Thunderbolt connection is missing altogether, restart your PC with the Device plugged and install the driver that came with the device.


How do I resolve an issue with a Device not detected or faulty on a Thunderbolt port?

Note: If you have Accidental Damage Cover, the damage is specifically covered as part of the Accidental Damage package. We must know where the damage is and how it occurred when you contact your local Technical Support. If you DO NOT have any cover or no Accidental Damage cover, then any repairs are chargeable.

You can check your warranty status on the link below.

The first step is to check the ports, the connector and the cable for any wear and tear or damage that might be causing you problems :

  1. Checking for damage is very basic, it is looking at the Thunderbolt ports and visually checking if there are any:

    • Cracks in the plastics surrounding the port?
    • Any part of the port crimped or bent?
    • Any pins from inside the port bent or missing?
    • Any parts of the port missing or broken off?
    • Any damage to the devices male connector?
    • Any damage to the cable from the connector to the device?
  1. If you identify any of the above, you must have in place an accidental damage warranty or be prepared for a chargeable repair call. (Your local Technical Support team provides a quote for this repair.)

  2. If there is no damage to the port or external device then carry on with the next step.

  3. Does the external Thunderbolt device work ok in another system?

    1. Yes, then proceed with the next step.

    2. No, then you must replace the external device.

  4. Plug the external device to the port. If you move the connector whilst it is plugged into the Thunderbolt port, does it affect whether the device is picked up or not?

    1. Yes, then contact your local Technical Support team to take the connection issue further.

    2. No, then proceed to the next step.

  5. Have you ruled out a software issue in any way? There are four basic ways to accomplish this.

    1. You can restart the PC with the Thunderbolt device plugged directly to the Port on its own. Once the PC has restarted, install the driver that came with the device. If it still does not work, then you must proceed with one of the remaining options. (a through d.).

    2. You can two way swap your HDD (Hard Disk Drive) with one from a similar working system and see if the fault follows the HDD to a new machine or if the issue stays with your system? Follow your User Guide for instructions on removing any hardware parts as the steps change from system type to the system type or you can search on our support site using terms such as "your PCs model type", "CRU" and "removal" to find a guide specific to your machine.

    3. You can boot from an Ubuntu Live CD (Regardless of the operating system currently in use on the PC.) and check to see if you experience the same issue in another OS. Ubuntu live CD's allow you to boot the OS off the CD without installing it on your Hard Drive. You can download an ISO of the CD on the Download link below. Tap rapidly at the F12 key when the system boots to the Dell Splash screen and choose the CD/DVD drive option from the boot once menu that appears.

    4. You can run a factory restore or reinstall your Operating system.

Caution: Carrying out option d. is done as a last resort and only done if one of the other two steps cannot be done. You MUST back up all data before carrying out this procedure - if you do not, data IS lost. Any operating system reinstall or factory restore involves formatting your Hard Disk Drive (HDD). Refer to the guides on the Windows portal for further information on these procedures.
  1. Was the issue seen once the OS and Software were ruled out?

    1. No, then the issue is resolved.

    2. Yes, then contact your support to take this further, they take you through some hardware diagnostics. These are built into your PC and you can also access more on the Dell Support Site by entering your service tag.

See the additional information section at the bottom of this article for contact us instructions.

Can I PXE Boot using Thunderbolt Ethernet Adapters?

Yes, you can, however, you must configure your BIOS to support this. See below:     

PXE Booting

Note: What is PXE Booting? - It is short for Pre-Boot Execution Environment. PXE is one of the components of Intel's (Wired for Management (WfM) specification. You can boot a system from a server at a stage prior to the normal boot process. This turns the system into a client PC that never boots from its internal Hard Drive.

Several options may need to be enabled in the BIOS to enable PXE booting.

  1. Check both the Legacy Option ROMs and the UEFI Network Stack :


  2. Enable Thunderbolt Boot support in the BIOS : (check all boxes).


  3. The server must support UEFI PXE Boot (Windows Server 2012 at minimum is required in most cases).

  4. Exit the BIOS and select UEFI PXE Boot IPv4.

  5. The WDS configuration for UEFI must contain x86 and x64 boot images.


How to run a Dell Diagnostic test on your Thunderbolt port

Dell has an online diagnostic tool to help identify and fix issues with your system.

  1. Go to the Dell PC Diagnostic page

  2. Click the Custom Component Test tab.

  3. Locate the listing for Thunderbolt / Display Port / USB.

  4. Select the one which matches your port.

  5. Click Run Diagnostics.

  6. Agree to Terms and Conditions in Legal Statement.

  7. Follow the instructions to test each port.

What is the future of the Thunderbolt port?

There does not appear to any doubt that the Thunderbolt standard is here to stay. Especially with the Type-C which is now promising ever more use. However, there still has not been a great uptake in converting to this standard. Currently, Thunderbolt users tend to be professionals who are in need of the benefits and quality of the standard in their jobs, much as they used to with the Firewire standard. I can see this following the same track as Firewire using high Quality and high-end devices, but the Type-C connectors ability to cross over and share markets with USB cannot be discounted.

What benefits does the Type-C USB standard bring? :

Improved Transfer Speeds
Type-C is a connector type, so currently we have to say the newest revision is Type-C using the Thunderbolt 4 standards. This Standard has transfer rates of 40Gbit/sec. We recommend that you check any devices you purchase with a Type-C connector to ensure it supports Thunderbolt if that's your intended use.
Improved Power Delivery
The Type-C supplies 100 Watts and it's bi-directional - so the same connection can either supply or receive power at the same time its transmitting data across the same connection. A large number of devices have swapped over to USB charging cables over the last few years and this development can only speed up this process further.
Improved Connector and Plug Design
The Type-C connector is both smaller and better designed than the old Mini DisplayPort connector. It is also able to take the place of the multitude of USB types currently in use. (Such as the Micro, Mini and Type-D connectors.) It's impossible to plug this cable in the wrong way round as it's reversible. It also leaves room for further improvements down the line.
Improved Protocols
The Type-C can support a number of different protocols using Alternate Modes. These allow you to have adapters that can output VGA, DVI, DisplayPort, HDMI or other types of connection from a single Thunderbolt port.
Simplifying the usage of Thunderbolt
The Type-C should lead to a more unified standard with 1 connector type and interchangeable cables and devices.

Intel Thunderbolt comparison chart

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Additional Information:


If your issue with another port on a PC, try the KB article 136835 below:    

If you require further assistance, contact Technical Support.
  Contact Us  

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Article Properties

Affected Product

Alienware 13 R2, Alienware 15 R2, Alienware 17 R3, Dell Thunderbolt Dock TB15, Precision 3510, Precision M3800, Precision 5510, Precision 7510, Precision 7710, XPS 12 9250, XPS 13 9350, XPS 15 9550

Last Published Date

29 Apr 2021



Article Type