External hard drives never had the reputation of being particularly fast. Only since the arrival of USB 3.2 external SSDs has portable storage started feeling "fast" enough for regular transfers. USB4 and Thunderbolt 4 SSDs have further pushed speeds to around 3,000 MB/s, thanks to 40 Gbps protocols. However, expecting this performance from a modern external SSD but getting significantly slower speeds is more common than people think. Having a fast SSD isn't enough; you also need the right USB-C port and cable to enjoy the maximum rated transfer speeds. The cable is often the silent point of failure in these scenarios, dropping performance to a fraction of what you expect. Not all USB-C cables are made the same, and manufacturers don't make it clear either. The onus is on you to identify the right cable and label it once you've found one.

Every link in the chain may be right, except for the cable

The one that you don't even suspect

External SSDs have come a long way in the last few years, and consumers finally have portable drives that can rival Gen3 NVMe SSDs in terms of transfer speeds. However, it isn't as simple as buying a USB4 or Thunderbolt 4 SSD and plugging it into a USB-C port on your desktop or laptop. Even if your USB-C port supports USB4 or Thunderbolt 4, as needed, you still need a USB-C cable supporting the respective standard. The wrong cable can make everything fall apart, leaving you stranded with speeds far below what your SSD is actually capable of.

All USB-C cables might look the same, but they can have wildly different specifications. For one thing, not all of them support data transfer. Some are only meant for power delivery or display output. Even if you're sure you have used your USB-C cable for data transfer before, there's no guarantee which USB standard it supports. Without testing it with your external SSD, you won't know the maximum speed it's rated for. USB-C has existed for a long time, so the cables in your drawers can range from terribly slow to extremely fast. Even an expensive cable might not support USB 3.2 Gen2x2 or USB4 speeds, which you most likely need for your modern external SSD. Plus, the length of the cable also affects the maximum speed, with shorter cables usually better adept at supporting faster standards.

Thinking you can use any USB-C cable lying around with your SSD to access its full potential is a recipe for disappointing performance. You might not even notice that your SSD is performing slower than it should if the speeds are relatively okay. Only when you keep an eye on the transfer dialog box will you notice something amiss.

Not all USB-C ports are the same, either

As if the cables weren't problematic enough

The problem is compounded by the fact that USB-C ports aren't always clearly labeled. Unlike USB-A ports that are color-coded to indicate the standard, USB-C ports on motherboards are labeled with the bandwidth they support. However, this isn't common on laptops or front panel ports on PC cases, so you still can't be sure about the ports' capabilities. Even the USB-C ports on one side of a laptop can have different maximum speeds than the ones on the other side. The average user is likely to plug their external SSD into the first matching port they see on their desktop or laptop, which is the worst strategy to adopt. Without consulting the manual or doing a few speed tests, you can't be sure if you're using the right USB-C port for your external SSD. And this isn't something the average user is likely to do, so they're often running their SSD at slower speeds without even realizing it.

Manufacturers and modern USB nomenclature aren't exactly helpful

Things have gotten more confusing over time

If only manufacturers labeled USB-C cables properly, we wouldn't be in this mess. You'll rarely see USB-C cables with the USB standard or bandwidth printed on them. I've only seen a handful of cables with the Lightning Bolt or "SS" (Super Speed) symbol. The former usually indicated Thunderbolt support, while the number next to the latter shows the maximum bandwidth (5, 10, or 20 Gbps). That said, this kind of labeling isn't universal by any means. Consumers are left to figure out their cables on their own. This lack of standardization has given rise to people considering every USB-C cable the same, and discovering their error too late.

Then, there's the USB nomenclature to worry about. Despite USB-C promising to make things simpler, we now have more confusion than ever over the same physical connector. Besides USB 3.2 Gen1, 3.2 Gen2, USB4, and Thunderbolt, you also have USB PD and DP Alt Mode on the same cable, making it near impossible to tell the difference unless you know where the cable came from. It's hard to keep up with the constantly changing naming schemes, which makes people just give up and use any USB-C cable on any USB-C port, and move on with their day.

Using the right USB-C cable is more important than ever

A few years ago, using a slightly older and slower USB-C cable wouldn't have tanked your external SSD's performance as much as it can today. The development of faster standards has widened the gap between the fastest and slowest USB-C cables, meaning consumers need to be extra careful about which cable to pick. More often than not, the wrong cable is the one thing tanking the performance of your modern external SSD, and you might not even notice it.