USB ports are pretty confusing by default, in the sense that they all look the same, but they are very far from the same. I already knew that, and yet, testing the ports on my PC case definitely gave me pause.

The reality is that outside of relying on colors (and even that isn’t infallible), there’s no easy way to tell at a glance what a USB port can or cannot do. So, I relied on software and some good old trial and error to figure out what mine are capable of, and there have been some surprises.

USB ports can be quite a mess

You probably don’t know what yours can do

Most PCs have more USB ports than most people ever really think about, and that’s part of the problem. Once everything is plugged in and working, it’s easy to treat every spare port like it’s basically the same thing in a different location.

As a result, we just … plug stuff in without thinking about it. Keyboard? Any port. External SSD? Whatever, just plug it in. Phone charger? Same thing.

That’s usually fine until you plug something fast into the wrong one and wonder why it’s suddenly crawling. That’s the easiest way to bottleneck a fast SSD.

The confusing part is that USB ports don’t make sense at a glance. Some are color-coded, but some only follow the old color conventions loosely, and others aren’t color-coded at all. A black USB-A port might be USB 2.0, but it might not be. A blue one probably means some version of USB 3.x, but who knows the exact speeds? You get the idea.

That’s why I wanted to finally stop guessing and memorize, once and for all, which port on my PC case is which. After testing them, though, it became pretty clear that convenience and capability aren’t the same thing. Some ports were exactly where I expected them to be, but some turned out to be better-suited to nothing but basic peripherals.

I mapped every USB port before testing anything

The first step was knowing which port was which

Credit: Jordan Gloor / How-To Geek

Before I could test anything properly, I had to make sure I wasn’t just randomly plugging my SSD into mystery ports and hoping for the best. So, I mapped my ports.

Front ports first, rear ports second, and everything numbered so I could match each benchmark result to the exact port used. I didn’t do this in any fancy way; I literally just drew them in a notebook and assigned them letters, because with my memory, I’d probably forget which is which before the experiment was done.

This is where I recommend you start: figure out where your ports are and label them. Then, it’s time for testing.

Windows showed me more than the port labels did

Some software can help you find out what your ports really are

Credit: Monica J. White / How-To Geek

Knowing where ports sit is one thing, but another is knowing what they really are on the inside. For this, you can use software, and in my case, I used HWiNFO.

HWiNFO made it much easier to decode everything. Under Ports > USB, it showed me the USB controllers, root hubs, and the devices currently hanging off each one. In my case, that meant a pile of AMD USB controllers, a bunch of empty ports, and several connected devices I could actually recognize, such as my peripherals or my TP-Link USB Ethernet adapter. It looks messy at a glance, but it was already much more useful than staring at a row of identical ports.

The important thing is that HWiNFO tells you what all is connected to your ports, and even what interface they are, but not which port is physically which in your case. So, I just had to plug a device in, watch what changed, and note down the final result once HWiNFO identified it for me. Instead of guessing, I could see when a device appeared under a different hub or controller, which helped me build a clearer picture of what my ports were doing.

HWiNFO was enough for what I needed here, but it isn’t the only option. Windows Device Manager can show similar information if you switch to View > Devices by connection, and tools like USB Device Tree Viewer or Microsoft’s USBView can also show the USB tree in more detail.

I used the same device to test real speeds

An SSD is ideal here

Credit: Patrick Campanale / How-To Geek

Once I had a rough idea of what Windows was seeing, I needed to find out what the ports could actually do. Specs and controller names are useful, but what I really wanted to know was simple: If I plug an external drive into each port, do I get the same speed every time?

The answer, unsurprisingly, was no. I already knew that, but not necessarily which ports to avoid. So, I used a few different devices to run tests, including an external SSD and a USB flash drive, and downloaded CrystalDiskMark for benchmarking purposes.

Above, you’ll see a couple of screenshots of the tool from when I tested it on my internal SSD and the USB flash drive. I’ll spare you the screenshots from every test, every port, and every device, but the general findings were as such: Some ports massively bottlenecked my SSD. Again, no surprise, but now I knew which ones.

To run this test, make sure you use the same device with the same high-speed data cable (rated for your SSD’s maximum speed) across every port, otherwise the cable itself will become the bottleneck. Don’t overthink the benchmark, either. For a test like this, the sequential read and write numbers are the easiest ones to compare, because they give you a clear idea of which ports are worth using for large file transfers and which ones should be left for peripherals.

Some ports were clearly meant for storage, and some were not

Fast ports deserve the toughest jobs

Credit: Tim Rattray/How-To Geek

The main lesson was simple, really. Just because an SSD fits a certain port, that still doesn’t mean you should be plugging it in just there. For instance, my fastest ports were not at the front of the case, but at the rear panel, and that might be the case for you, too.

Lesson learned here is to use your best ports for your best devices, and that’ll always come down to a fast NVMe SSD. A keyboard won’t be bottlenecked by USB 2.0, but an SSD very much will.

Testing my USB changed how I use my PC

I didn’t uncover some massive disaster, but I did realize that I’ve been using the wrong ports for data transfers for years. I now know which ports to use when speed matters, and which ones are best left for low-bandwidth peripherals, and it only took me around 10 minutes to find out once and for all which is which.