For the better part of a decade, the iPhone had its Lightning connector while the rest of the world gradually moved to USB-C. That era is firmly over. Since the iPhone 15, every iPhone ships with USB-C. Every iPad has had it for years. Most Android phones, laptops, tablets, wireless earbuds, and even some cameras now use the same port. The European Union mandated USB-C as a common charger standard by the end of 2024, which pushed the holdouts along nicely. In theory, this is wonderful — one cable to rule them all. In practice, there is a lot more nuance to it than the marketing suggests, and we see the confusion play out every single day here at GenioTech.
The Port Shape and the Technology Inside Are Two Different Things
This is the most important thing to understand about USB-C, and it trips up a lot of people. USB-C refers to the physical shape of the connector — the small oval port that can be inserted either way up. What it does not tell you is anything about the data speeds or charging power that cable or device actually supports. A £3 cable from a market stall and a £30 cable from a reputable brand can look absolutely identical on the outside, but perform completely differently.
The underlying technology varies enormously. The most basic USB-C cables carry USB 2.0 data speeds — that is around 480 megabits per second, which is the same speed as a decent USB stick from 2010. The vast majority of cheap USB-C cables are USB 2.0. For charging your phone, this is perfectly fine. For transferring large video files, it is painfully slow. Step up to USB 3.2 and you get transfer speeds of up to 10 or 20 gigabits per second depending on the generation. USB4 — note, no hyphen, that is intentional — pushes up to 40Gbps, and Thunderbolt 4, which is common on Apple Silicon MacBooks, also runs at 40Gbps with additional features like support for external displays at high resolution.
What does all this mean in practice? If you are just charging your phone and occasionally syncing files, a standard USB-C cable is absolutely fine. If you are a photographer or videographer transferring large files from a camera or external drive, or a MacBook user connecting high-resolution external displays, cable spec genuinely matters and is worth looking into before you buy.
Charging Speeds: Watts, Power Delivery, and Why Your Charger Matters
The other half of the USB-C confusion is charging. The wattage of a charger — 5W, 20W, 65W, 140W — tells you how much power it can potentially deliver. A higher wattage charger will charge a device faster, up to the maximum the device itself is designed to accept. A modern iPhone, for example, supports fast charging when paired with an appropriate charger and cable. Plug any iPhone into an old 5W charger via a USB-C adapter and it will charge — just very slowly, particularly overnight if your battery is significantly depleted.
Power Delivery, often shown as USB-PD or simply PD, is the standard protocol that allows a charger and a device to negotiate the optimal charging speed together. When you plug a PD-capable charger into a PD-capable device, they communicate and agree on the highest safe wattage for that particular device at that moment. This is why you can use your MacBook charger for your iPhone without any concern about damaging the phone — the phone tells the charger what it wants, and the charger obliges. The device draws only what it needs, never more.
For most everyday phone users, the practical answer is simple: get a 20W or higher USB-C PD charger and pair it with a decent cable from a reputable brand. That combination will give you fast charging on most modern iPhones and Android flagships. If you want to charge a laptop from the same brick, look for a 65W or 100W PD charger with multiple ports. We stock multi-port 65W chargers in-store at GenioTech that will comfortably charge a phone and a laptop simultaneously — genuinely useful on a busy desk.
Do All USB-C Cables Charge at the Same Speed?
No — and this is probably the most misunderstood thing about USB-C. The charging speed depends on both the cable and the charger working together. A poor quality cable can act as a bottleneck, limiting the wattage that flows through it even if your charger is perfectly capable. Some very cheap cables have also caused issues by failing to correctly communicate resistance values to the device — this can in rare cases cause a charger to deliver inconsistent power levels, leading to slower-than-expected charging or in some cases, heat.
The solution is not to spend a fortune. Cables from well-regarded brands such as Anker, Belkin, Ugreen, and Apple’s own first-party cables are well-made, properly certified, and reasonably priced. A good USB-C cable costs between £8 and £20 depending on length and specification. Avoid unbranded cables from unknown sellers, especially if you are using them with higher-wattage chargers for laptops or tablets where the power draw is significantly higher.
What Cable and Charger Do You Actually Need?
Let us make this practical. Here is a straightforward guide based on what you are trying to do:
Just charging a phone: Any USB-C cable from a reputable brand, paired with a 20W or higher USB-PD charger. You will get fast charging on all modern iPhones and most Android flagships. This covers the vast majority of people reading this.
Charging a phone and a laptop from one plug: A 65W multi-port USB-PD charger with at least one USB-C port on each output. One brick, one cable per device, both charge at useful speeds without competing with each other too much.
Transferring files from a camera, SSD, or high-speed storage device: Check the specification of your device and buy a cable rated to match — USB 3.2 Gen 2 at minimum for fast transfers, USB4 if your device supports it. The difference in transfer time for a 100GB folder is genuinely dramatic.
MacBook with an external display at full resolution: You will want a Thunderbolt 4 cable for full display bandwidth and data speed. These cost more than a basic USB-C cable but are essential for driving high-resolution monitors without signal issues.
Laptop fast charging: Check the wattage your laptop requires in its specification sheet. A 100W or 140W USB-PD charger handles even the most power-hungry MacBook Pro models comfortably.
A Note on Cable Quality and Safety
We have seen phones and laptops come into GenioTech after people have been using very cheap, unbranded cables for extended periods. While modern devices do have built-in protections, consistently sluggish charging — unusually slow speeds, the device appearing to not recognise it is connected, or the cable getting warm — is often down to a substandard cable rather than anything wrong with the device itself. It is the first thing we check when someone reports charging problems, and in many cases swapping the cable immediately resolves the issue.
Investing in a decent cable is one of the cheapest forms of device protection there is. It costs far less than any repair, and it protects your device from the kind of low-level stress that a bad cable can introduce over time.
In-Store at GenioTech, Hilltown, Dundee
At GenioTech, we stock a carefully chosen range of quality USB-C cables and chargers — including multi-port 65W PD chargers, individual fast-charge phone chargers, and cables in various lengths for different situations. Everything we sell is from reputable manufacturers and we have tested it ourselves. We do not stock the cheap stuff, because we have seen the results.
If you are not sure what cable or charger you need for your particular combination of devices, come and have a chat. We are on Hilltown, open Monday to Saturday, 9am to 5pm. No appointment needed. You can also have a look at our services page for the full range of what we do, or get in touch if you want to ask a question before you come in.
USB-C being universal is genuinely a good thing for everyone who has ever rummaged through a drawer full of cables looking for the right one. It just comes with a small learning curve — and now you have got it sorted.