Your laptop's USB-C ports aren't all equal, and there's a way to tell

1 day ago 2

Published Nov 2, 2026, 11:46 AM EST

Kanika began writing about consumer technology in 2019 and has contributed to tech websites like Beebom and The Mac Observer. During her journey, she covered a wide range of topics, including Android, Windows, AI, and everything Apple. She has been a loyal iPhone user since 2014, and owns an Apple device from almost every lineup. With a keen eye on the latest trends, she strives to help users get the most out of their gadgets.
Beyond her love for writing, she is a deep researcher and a lifelong learner, always eager to explore the latest innovations and emerging technologies. With her passion for technology and writing, she joined MUO in 2025 as a Freelance Tech Writer.
When not writing, she's probably trying a viral Instagram recipe or watching some thriller suspense on Netflix.

Recently, I splashed and bought a shiny new monitor. I brought it home and plugged my new monitor into my laptop’s USB-C port, but nothing happened; when I switched to the other USB-C port, my screen lit up instantly. Now, I assumed that plugging a USB-C accessory into any port would give me the same results. After all, the connector looked identical, so I had no reason to suspect the ports were different.

Well, the thing is, USB-C describes the connector's shape, not everything it can do. That’s why two ports on your laptop can have different capabilities, even if they look the same.

That USB-C port might not do what you think

USB-C is a connector, not a standard

USB-C describes the shape of the connector: small, oval, and reversible. However, it doesn’t tell you what the port can exactly do for you. Depending on your laptop, a USB-C port might transfer data, offer USB Power Delivery for charging, connect to an external display, or, most typically, support a combination of these features.

Laptop manufacturers decide which features each port supports. More advanced features, such as Thunderbolt, require additional hardware, which can increase manufacturing costs. That's why some laptops have one or two fully featured USB-C ports and others with basic capabilities.

So, when you see “USB-C” on a spec sheet, it doesn’t reveal the full picture. In the worst case, some USB-C ports may support only USB 2.0 speeds, which is slower than the older (and now replaced) USB-A ports.

The four things that can differ between ports

Here’s what matters

USB-C ports mainly differ on four fronts. The first one is obviously the data transfer speed, and the naming doesn’t help. Here are USB-C port generations and speeds:

Standard

Max speed

Year

USB 2.0	480Mbps	2000
USB 3.2 Gen 1 (originally USB 3.0)	5Gbps	2008
USB 3.2 Gen 2 (originally USB 3.1)	10Gbps	2013
USB 3.2 Gen 2x2	20Gbps	2017
USB4	20Gbps or 40Gbps	2019
Thunderbolt 3 / Thunderbolt 4	40Gbps	2015 / 2020
USB4 Version 2.0	80Gbps (up to 120Gbps asymmetric)	2022
Thunderbolt 5	80Gbps (up to 120Gbps with Bandwidth Boost)	2023

These speed differences matter when you’re transferring large files to an external SSD or backing up your laptop, or anything else involving large data transfers.

The second difference is whether your USB-C port can output video or not. Some laptops support DisplayPort over USB-C, while others might only handle data and charging. If you want to connect an external monitor to your laptop, you need a port and cable that support video output.

Some USB-C ports support Thunderbolt and USB4, which provide high-speed data transfer and let you connect displays and docks. However, a basic USB-C port may not support these features. High-end laptops like some MacBooks and professional Windows machines offer 2 to 4 Thunderbolt ports, whereas mid-range laptops have just one or none.

Then comes charging and power delivery. A USB-C port might charge your laptop, charge a connected phone, or supply power to accessories, but the amount of power it can deliver or accept varies. If a port can charge your phone, it won't necessarily charge your laptop, especially under heavy workloads. So, you have to pay attention to that.

Look for the tiny symbols next to the port

The physical clues

Side view showing two USB-C and one USB-A port

Some manufacturers etch small icons beside each port, and they’re the fastest way to understand what your USB-C port can do. So, before you dig into settings or search online, I recommend taking a closer look at your laptop's ports.

Lightning bolt: The port supports Thunderbolt, which means 40Gbps or more and usually video and charging too. SS with a number: SuperSpeed USB, where SS 5, SS 10, and SS 20 match the Gbps. USB logo with 20 or 40: a USB4 port at that speed. DisplayPort logo: The port supports video output. Battery or plug icon: the port can charge the laptop.

The tricky part is that manufacturers don't always label their ports clearly. You might notice that some laptops have no symbols at all, whereas others might have similar-looking markings for different capabilities. Also, if you don’t see a Thunderbolt or DisplayPort symbol, it doesn't always mean your port lacks those features.

Find exact port specifications

Let's get to a more reliable way

If you can’t find any markings on your laptop ports, you can check the manufacturer's documentation for your exact laptop model. This is the most reliable way to identify your USB-C ports.

You can also find details on your machine itself. If you own a Mac, go to the Apple menu -> About This Mac -> More Info -> System Report. You will see the connected devices and their speeds in the USB and Thunderbolt sections.

If you're using Windows 11, you'll see a USB page under Settings -> Bluetooth & devices that shows USB4 details on supported machines. In case you want per-port details, I would recommend using a free tool called USB Device Tree Viewer, which shows the speed each connected device negotiated.

Test your USB-C port

Check what’s working for you

Specs tell you what a port should do, and it's a good idea to run a quick test to see what the port does. Here's what you can do:

To test data speeds, connect an external SSD and copy a large file. You can also use a speed-testing tool like CrystalDiskMark on Windows or Blackmagic Disk Speed Test on Mac. Connect an external monitor with a video-compatible USB-C cable to check if your USB-C port supports display output. To check charging, plug in a compatible USB-C charger and see if your laptop charges.

Just remember that the results depend on more than the port itself. So, if something doesn't work right, I would recommend checking your laptop's specifications, cable, and accessories before you blame the port.

Brand FNIRSI

USB Version USB-C, MicroUSB, USB-A

FNIRSI USB Tester is a compact diagnostic tool that measures voltage, current, power, capacity, and charging protocols over USB-A and USB-C. Ideal for troubleshooting cables, chargers, and devices, it gives real-time readings, fast-charge detection, and clear on-screen data for quick, confident checks during everyday testing and deeper power analysis tasks.

What to check before you buy your next laptop

Even if your laptop's USB-C port supports fast data transfer, video output, or fast charging, your cable must support those features too. Not all USB-C cables offer the same speeds, video capabilities, or power levels, so check the cable's specifications before assuming the port is the problem.

Before buying your next laptop, check what each USB-C port supports and whether it meets your needs for external monitors, SSDs, chargers, and docking stations. Don't just count the USB-C ports when choosing a laptop. Check what each one can actually do.

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