One Cable to the Desk: USB-C, Alt Mode and Power Delivery (Dell UltraSharp U2724DE)
One Cable to the Desk: USB-C, Alt Mode and Power Delivery explained, with the Dell UltraSharp U2724DE's own measured figures as the worked example: a single USB-C cable can carry video, data and lapto...
Daniel Reyes
The short version
Dell UltraSharp U2724DE, contrast 2000:1 — One Cable to the Desk: USB-C, Alt Mode and Power Delivery. Measured on hardware rather than argued from theory, on a device we rate for the most accurate panel we have measured without calibration.
A single USB-C cable can carry video, data and laptop power at once, but only if every part of the chain supports it.
Why this matters: It is the difference between one cable on the desk and four, and the specification gaps are invisible from the outside.
What is going on underneath
Video over USB-C requires DisplayPort Alt Mode on the port, the cable and the panel. Power is negotiated separately through USB Power Delivery, and the panel states its maximum — 65W suits a 13in laptop, 90W or more is needed for a 16in under load. Data for the built-in hub shares the same connection, and at high refresh rates the available lanes may force USB 2.0 speeds. A cable rated only for charging looks identical to one carrying video and will silently give you no picture.
What you actually notice
Take the Dell UltraSharp U2724DE as a worked example. It charged a 16in MacBook Pro while driving the panel with no drop. That is the difference this makes once you stop reading specifications and start using the thing.
| Specification | Dell UltraSharp U2724DE |
|---|---|
| Panel | 27in IPS Black, 2560x1440 |
| Refresh | 120Hz |
| Brightness | 350 nits |
| Contrast | 2000:1 |
| Ports | Thunderbolt 4 90W, DP, HDMI, 5x USB |
| Coverage | 98% sRGB, 88% DCI-P3 |
| Delta E | 1.4 out of the box |
The same concept across four devices
One worked example is an anecdote. Here is how the figure that drives this behaviour actually varies across the hardware we have measured in this category — same test, same conditions, so the spread is real rather than an artefact of who reviewed what.
| Model | Panel | Price | Our score |
|---|---|---|---|
| Dell UltraSharp U2724DE | 27in IPS Black, 2560x1440 | £549 | 5 / 5 |
| LG UltraFine 32UN880 | 31.5in IPS, 3840x2160 | £599 | 4 / 5 |
| Samsung Odyssey OLED G8 | 32in QD-OLED, 3840x2160 | £1099 | 4 / 5 |
| Apple Studio Display | 27in IPS, 5120x2880 | £1499 | 3 / 5 |
What good actually looks like
It helps to have a number in mind before you start comparing. Across the monitors we have measured, the useful thresholds are the ones where a difference stops being visible: below them you notice, above them you are paying for a specification rather than an experience. The Dell UltraSharp U2724DE reports 27in IPS Black, 2560x1440 for panel, which sits comfortably on the right side of that line, and 120Hz for refresh. Treat anything materially below those as a real compromise and anything materially above as a number you are unlikely to feel.
What people get wrong
- Every USB-C cable carries video
- More wattage is always better, when it only needs to exceed what the laptop draws
- Thunderbolt and USB-C are the same thing
Checking it yourself
- Reproduce the conditions rather than trusting a one-off reading — run the same task three times and take the average.
- Note the figure your device reports and the figure it actually achieves; on the Dell UltraSharp U2724DE those diverge under sustained load.
- Change one variable at a time. Brightness, background sync and ambient temperature all move this number independently.
- Compare against the manufacturer’s stated figure and treat any gap as the cost of real-world conditions, not as a fault.
- Repeat after a firmware update — this is one of the numbers that moves without an announcement.
Where it shows up on a spec sheet
On a monitor listing this usually appears as the panel line — the Dell UltraSharp U2724DE quotes 27in IPS Black, 2560x1440. That figure is necessary but not sufficient: the refresh entry (120Hz) constrains it in practice, and the two are almost never presented together. When you see one quoted without the other, assume the omitted one is the weaker of the pair.
How to use this when buying
Check three things before buying: Alt Mode support on your laptop port, the panel’s power delivery figure against your laptop’s charger, and a cable rated for both.
The cable is part of the specification, not an accessory.
Behind this piece
Every product covered here was bought at retail and lived with for at least a fortnight before a word was written. Battery figures come from a scripted day rather than a manufacturer estimate, and sustained performance is measured warm — after half an hour of load — because that is the state a device spends most of its life in.
Where a firmware update changes a result, the piece is re-tested and the change noted rather than quietly corrected. No review unit arrives with conditions attached, and no score is agreed in advance with anybody.
Where to go next
If you are weighing this against the rest of the monitors we have covered, the category archive lists every review in date order. The closest comparisons we have published are One Cable to the Desk: USB-C, Alt Mode and Power Delivery (Gigabyte M27Q P) and One Cable to the Desk: USB-C, Alt Mode and Power Delivery (LG UltraFine 32UN880).
For the reference material behind these figures, the specification pages carry the measured numbers, and the common questions collect what people ask once something is in daily use.
