Dell U4025QW on a Mac: 120 Hz, scaling and window layouts
By Guido Crego · Last updated:
The U4025QW works with Apple silicon Macs over one Thunderbolt cable that also charges a laptop, at up to 140 W. Owners get 120 Hz on M2 Pro, M3 Max and M4 Macs; M1 Pro and Max owners report 60 Hz. The sharp setting most people want, 3840 × 1620 in HiDPI, works on Pro and Max chips, and on M4 Macs it only shows up at 120 Hz.
| Size | 40" |
| Resolution | 5120 × 2160 (21:9) |
| Column widths at 5120 × 2160 | ½ 2560 · ⅓ 1707 · ¼ 1280 |
| Column widths at 3840 × 1620 | ½ 1920 · ⅓ 1280 · ¼ 960 |
| Column widths at 2560 × 1080 | ½ 1280 · ⅓ 853 · ¼ 640 |
This page is about Dell’s 40-inch UltraSharp U4025QW: 5120 × 2160 (21:9, often called 5K2K), 120 Hz, on sale since February 2024 (TechPowerUp). Its predecessor, the U4021QW, runs at 60 Hz, so the 120 Hz parts don’t apply to it. Everything here was checked on October 8, 2026; reports from owners say so and link to the thread.
The cable: one Thunderbolt cable
The U4025QW has a Thunderbolt 4 input that carries the picture and up to 140 W of charging, plus DisplayPort 1.4 and HDMI 2.1 inputs, a Thunderbolt 4 downstream port and 2.5 Gb Ethernet (Dell). With a MacBook, that one cable is the whole desk: screen, power and the monitor’s ports.
For 120 Hz, the connection has to carry compressed video (DSC). When an M1 MacBook Pro owner asked, Dell staff quoted the guide: 5120 × 2160 at 120 Hz “can only be produced with Thunderbolt DP-ALT 1.4 DSC, DP 1.4 DSC, or HDMI 2.1 video source” (Dell Community, 2025). So whether you get 120 Hz depends on the Mac as much as on the cable.
What refresh rate each Mac gets
Apple doesn’t list this monitor. Its spec pages give one external display at up to 5K and 120 Hz for the M4 MacBook Pros (Apple), the M5 Pro and Max (Apple) and the M5 MacBook Air, whose page mentions “DisplayPort 1.4 speeds (up to HBR3) with DSC capability” (Apple). For older chips, this is what owners report:
| Mac | Reported | Source |
|---|---|---|
| M1 Pro, M1 Max, M1 Ultra | 60 Hz. A custom EDID made in BetterDisplay got some owners 100 to 110 Hz | MacRumors, 2024 |
| M2 Pro | 120 Hz over Thunderbolt, with “looks like 3840 × 1620” | MacRumors, 2024 and 2025 |
| M3 Max | 120 Hz | MacRumors, 2024 |
| Mac mini M4 | 120 Hz over a USB-C-to-DisplayPort cable, with “looks like 3840 × 1620” | MacRumors, 2024 |
| Mac mini M4 Pro | 120 Hz and 3840 × 1620 out of the box | MacRumors, 2026 |
The M1 Pro and Max result matches Apple’s spec for those chips, which stops at 6K and 60 Hz (Apple). Dell’s list includes HDMI 2.1, and Apple’s fastest HDMI modes need an Ultra High Speed 48 Gbps cable and no adapter (Apple), but we haven’t found an owner report of this monitor at 120 Hz over HDMI on a Mac. The reports above use Thunderbolt or USB-C-to-DisplayPort.
Scaling: why 3840 × 1620 is the one to aim for
At native 5120 × 2160, macOS runs the screen at 1×. The panel has 140 pixels per inch (Dell, above), so text comes out smaller than on a 27-inch 1440p monitor, which has about 109.
macOS’s sharp “looks like” modes draw everything at twice the size and scale it down, so looking like 3840 × 1620 takes a 7680-pixel-wide image (BetterDisplay wiki). How wide a Mac can go depends on the chip:
- M1, M2 and M3 Pro, Max and Ultra: up to 3840 points wide, so 3840 × 1620 works (BetterDisplay wiki).
- Base M1, M2 and M3: up to 3072 points. One M3 MacBook Air owner topped out at 3072 × 1296 (MacRumors, 2024).
- M4 and M5: usually 3360 points, a cap one developer traced to the display firmware (smcleod.net, 2026). M4 owners with 5K2K monitors lost 3840 × 1620 when those Macs came out (9to5Mac, 2024).
The U4025QW was the exception. On M4 Macs, owners found its 3840 modes listed only at 120 Hz: pick 60 Hz and they’re gone (MacRumors, 2024). That’s why this Dell kept its sharp mode on M4 while 5K2K monitors without a 120 Hz mode lost it. On an M4, no 120 Hz means no 3840 × 1620.
macOS 27 (out since September 14, 2026) changed this for those other monitors. Apple says “Now you can get higher resolutions on ultrawide displays, such as 5K at 120Hz” (Apple), and owners report 3840 × 1620 back on M4 and M5 Macs with 5K2K screens like LG’s 40WP95C and Dell’s own U4021QW (MacRumors, 2026). One catch from the same thread: a base M4 or M5 MacBook Air driving a second external display drops to 3008 or 3072 wide.
The other options: “looks like 2560 × 1080” is exactly 2×, sharp on every Mac, but everything is big. Anything wider than 3840 points runs at 1×, since no Mac renders HiDPI wider than that. If 3840 × 1620 isn’t in the list, open System Settings → Displays → Advanced, turn on “Show resolutions as list” and then “Show all resolutions” (Apple).
Firmware
Dell ships this monitor’s firmware with a macOS installer.
- M3T104 (April 2025, optional) stops an on-screen menu from popping up when Dell’s app assigns USB in picture-by-picture (Dell).
- M3T105 (October 2025, recommended) adds an option to switch inputs automatically when the Thunderbolt computer sleeps, a power delivery patch Dell lists for MacBook restart compatibility, and a USB hub fix for KVM switching (Dell).
The Mac updater broke on macOS Tahoe 26.0.1: it said the firmware wasn’t for this monitor. Dell put it down to a change in macOS, and owners updated fine after moving to macOS 26.2 in December 2025 (Dell Community, 2025).
Common problems
- No 120 Hz. Use Thunderbolt or a DisplayPort connection with DSC (see Dell’s list above). On M1 Pro, Max and Ultra, owners get 60 Hz; some reached 100 to 110 Hz with a custom EDID in BetterDisplay.
- 3840 × 1620 isn’t in the list. Turn on “Show all resolutions”. On an M4, pick 120 Hz first. One M4 Pro Mac mini owner lost both 3840 × 1620 and 120 Hz after updating to macOS 26.6.2 (MacRumors, 2026).
- Kernel panics after sleep. An M3 Max MacBook Pro powered by the monitor over Thunderbolt kept restarting with kernel panics after sleep. Dell blamed firmware M3T103 and replaced the monitor; the panics stopped after the owner updated to macOS 15.1.1 (Apple Community, 2024). M3T105 came later with its MacBook restart patch; we don’t know if it’s the same bug.
- Volume is greyed out, or Dell’s app crashes. Owners report both and switch to MonitorControl, BetterDisplay or DisplayBuddy (Dell Community, 2024).
Dell’s own zones: Easy Arrange
Dell Display and Peripheral Manager (DDPM) for macOS has a feature called Easy Arrange, and the U4025QW is on its list. Dell describes it as “Select from integrated screen layouts to divide your display into zones” and “Drag applications to zones, they automatically snap into place”. It can also save a layout from windows you’ve arranged, and has keyboard shortcuts to snap windows to screen regions. Dell lists full support on Apple silicon with macOS 14, 15 and 26 and limited support on macOS 27, and says it needs DDC/CI turned on and a USB upstream connection (Dell).
Shoji · window zones for Mac works with any brand, so the MacBook’s screen and a monitor from another maker get zones too, while DDPM covers the Dell monitors on its list. You draw the zones yourself, right on the screen, any size and overlapping if you want. Each monitor keeps its own layouts: Shoji recognizes it by its hardware and brings them back when you plug it in again. Owners also report DDPM crashing on macOS (Dell Community, 2024).
Splitting 5120 × 2160 into windows
macOS tiles windows into halves and quarters only (Apple). At “looks like 3840 × 1620”, half the screen is 1920 points: the width of a whole 1080p monitor for one window. Columns work better. The table at the top has the widths for each resolution; at 3840 × 1620:
- Thirds give each window 1280 points, about the width of a small laptop screen.
- A wide center with narrow sides (25 / 50 / 25) gives 960 / 1920 / 960: the window you work in sits in front of you, and the sides hold a chat or notes.
- Notes, a wide center, and two windows stacked on the right, the layout in the demo above: the right column is 960 points wide and each window in it gets 810 points of height.
At native 5120 × 2160, thirds are about 1707 points each. On a base M1, M2 or M3 at 3072 points, thirds are 1024 and a wide center is 768 / 1536 / 768. For more 21:9 layouts, see ultrawide monitors on a Mac; for the other 5K2K on this site, the LG 45GX950A; for the smaller Dell, the U3425WE.
Set it up with Shoji
Shoji · window zones for Mac lets you draw these layouts and snap windows into them.
- Open Shoji and allow Accessibility when macOS asks. Any app needs it to move other apps’ windows.
- From the Shoji menu in the menu bar, choose “Edit Zones” and pick the U4025QW.
- Start from “Thirds” or “Center + sides”, or drag on the screen to draw your own zones. They snap to a 12 × 8 grid, so thirds land on 4 / 4 / 4 twelfths and a wide center on 3 / 6 / 3.
- Save. Hold fn while you drag a window: the zones light up. Let go over one and the window fills it.
The Dell keeps its own layouts. If it sits next to a MacBook, the laptop screen has its own zones, and when you unplug the Thunderbolt cable, the Dell’s layouts wait for it until you plug it in again.
Questions
Does the U4025QW run at 120 Hz on a Mac?
On M2 Pro, M3 Max and M4 Macs, owners report 120 Hz over Thunderbolt or USB-C-to-DisplayPort. M1 Pro, Max and Ultra owners report 60 Hz. Dell says 120 Hz needs DSC over Thunderbolt or DisplayPort 1.4, or HDMI 2.1.
What’s the best scaling for the U4025QW on a Mac?
“Looks like 3840 × 1620” if your Mac offers it: it’s sharp, and it’s the most room you can get in HiDPI. Native 5120 × 2160 gives more room but runs at 1×, with text smaller than on a 27-inch 1440p screen. “Looks like 2560 × 1080” is sharp, but everything is large.
Does it work with a Mac mini M4?
Yes. A base M4 Mac mini owner reports 120 Hz and “looks like 3840 × 1620” over USB-C-to-DisplayPort, and an M4 Pro mini got both out of the box. Keep it at 120 Hz: on M4, the 3840 modes aren’t listed at 60 Hz.
Does it work with a MacBook Air?
Yes. The M1 and M2 Airs drive one external display at up to 6K and 60 Hz (Apple), and the M5 Air is rated for 5K at 120 Hz. On base chips, the sharp modes stop at 3072 points wide, so one M3 Air owner got 3072 × 1296. We haven’t found an owner report for the M4 Air yet.
Do I need a driver or Dell software on a Mac?
Dell’s Mac software is Display and Peripheral Manager (monitor settings and Easy Arrange) and the firmware updater. The resolution and refresh rate are set in macOS’s own Displays settings. If DDPM crashes or greys out the volume, owners use MonitorControl, BetterDisplay or DisplayBuddy instead.
Shoji · window zones for Mac
Draw zones on each monitor, drag a window over one, and it snaps in. $4.99 once; if it isn't for you, your money back within 14 days.
$4.99 once · one Mac · macOS 15 or later