LG UltraGear 45GX950A on a Mac: resolution, scaling and window layouts
By Guido Crego · Last updated:
The LG 45GX950A works with a Mac over one USB-C cable, which also charges a MacBook at up to 90 W. Out of the box macOS shows it as "looks like 2560 × 1080", so everything is huge; turn on "Show all resolutions" to pick about 3200 × 1350 or 3840 × 1620. Whether you also get 165 Hz depends on the chip, the port and the macOS version.
| Size | 45" |
| 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 LG’s 45-inch UltraGear 45GX950A (sold as 45GX950A-B): a curved 21:9 OLED at 5120 × 2160, or 5K2K. There’s also a newer 45GX950B. We haven’t confirmed how it differs, so nothing here was checked on it. The 40-inch Dell U4025QW has the same resolution and its own page. Everything here was checked on October 8, 2026; reports from owners say so and link to the thread.
One USB-C cable, or HDMI
The 45GX950A has a USB-C port with DisplayPort Alt Mode and 90 W of power, plus two HDMI 2.1 inputs and a DisplayPort 2.1 (LG spec sheet). For a MacBook, that means one USB-C cable carries the picture and charges the laptop.
LG’s manual lists the full 5120 × 2160 at 60, 100 and 165 Hz, with no 120 Hz. It also says the USB-C port runs as DisplayPort 1.4, and that the top modes need a graphics chip with DSC (Display Stream Compression) (LG manual).
What refresh rate a Mac gets
Apple doesn’t publish numbers for this monitor, so this is what owners report:
| Chip | Reported | Source |
|---|---|---|
| M1 Pro | “Looks like 3840 × 1620” at 100 Hz | Apple Community, 2026 |
| M3 Pro | 3840 × 1620 at 165 Hz, with HDR, over USB-C | Apple Community, 2026 |
| M4 Pro | 165 Hz, but only with HDR off | Apple Community, 2026 |
| M5 Pro, macOS 26 | Over USB-C: no 3840 × 1620 and no 165 Hz. Over the Mac’s HDMI port: both | Apple Community, 2026 |
| M5 Pro, macOS 27 beta | 3840 × 1620 and 165 Hz back, still no HDR | MacRumors, 2026 |
On the M5 Pro, a USB-C-to-HDMI adapter hit the same limit as USB-C; only the Mac’s own HDMI port gave the full modes. Apple asks the same for its fastest HDMI modes: an Ultra High Speed 48 Gbps cable and no adapter (Apple). Then macOS 27 arrived with “higher resolutions on ultrawide displays, such as 5K at 120Hz” (Apple), and owners in the Apple Community thread say updating fixed it.
The monitor also has a dual mode that drops it to 2560 × 1080 at 330 Hz (LG spec sheet). It’s meant for games, and we haven’t seen a Mac owner report running it.
Why everything looks huge at first
macOS’s sharp “looks like” modes draw everything at twice the size and scale it down (BetterDisplay wiki). On this monitor macOS picks “looks like 2560 × 1080” by default: exactly half of native each way, very sharp, and “enormous at that physical size”, as an M3 Max owner put it. In System Settings → Displays → Advanced, turn on “Show resolutions as list” and then “Show all resolutions” (Apple). That owner, on macOS 15, then got the in-between modes: about 3200 × 1350 and 3840 × 1620 (MacRumors, 2026).
Native 5120 × 2160 runs at 1×. The panel has about 125 pixels per inch (LG spec sheet), denser than a 27-inch 1440p monitor at about 109, so text comes out smaller than on one. Owners in this MacRumors thread find native too small and talk about scaled modes instead. By our arithmetic from LG’s pixel pitch, “looks like 3840 × 1620” makes things a little bigger than on a 27-inch 1440p screen, and 2560 × 1080 makes them about 1.7 times as big.
How wide a sharp mode can go depends on the chip. “Looks like 3840 × 1620” needs a 7680-pixel-wide image, which M1, M2 and M3 Pro, Max and Ultra chips make; base M1, M2 and M3 chips stop at 3072 points wide (BetterDisplay wiki). M4 and M5 chips usually stop at 3360, with 3840 showing up on some monitors that offer 100 or 120 Hz timings (smcleod, 2026). On macOS 27, owners report 3840 × 1620 back on several 5K2K monitors with M4 and M5 Macs (MacRumors, 2026).
Common problems
- 3840 × 1620 isn’t in the list. Turn on “Show all resolutions” first. On an M5 Pro with macOS 26, it doesn’t show up over USB-C at all: use the Mac’s HDMI port or update to macOS 27, as in the table above. Owners describe the same M5 Pro and Max limits with other monitors (Reddit, 2026).
- No 120 Hz, or no 165 Hz. The monitor has no 120 Hz mode; pick 100 or 165. If 165 is missing on an M4 Pro, one owner got it only with HDR off.
- Colored edges on small text. This WOLED panel shows red and green fringing on small macOS text (MacRumors, 2026), and rtings notes “some fringing issues around text” (rtings). Some owners don’t notice it; others return the monitor within a week. Keep the box until you’re sure.
- The screen flickers. Apple says variable refresh “might produce a flickering or stuttering effect”; turn Adaptive Sync off (Apple).
- An M2 Mac restarts on its own. An r/MacOS thread reports kernel panics on M2-series Macs running macOS 26 with high-resolution, high-refresh monitors (Reddit, 2026). If it happens to you, that thread is where owners compare notes.
LG’s own app
LG’s OnScreen Control has a Screen Split feature on some LG monitors, with preset splits, but support depends on the model and the macOS version, and we couldn’t confirm it for the 45GX950A. Check the downloads on LG’s page for the monitor.
Shoji · window zones for Mac works with any brand, so the MacBook’s screen and a monitor from another maker get zones too. You draw the zones yourself, right on the screen, any size and overlapping if you want. And each monitor keeps its own layouts: Shoji recognizes the LG by its hardware and brings them back when you plug it in again.
Splitting the 45GX950A into windows
macOS tiles windows into halves and quarters only (Apple). At “looks like 3840 × 1620”, half the screen is 1920 points: as wide as a whole 1080p monitor, for one window. Columns work better. The table at the top has the widths for each mode; in practice:
- Three columns at 3840 × 1620 give each window 1280 points, about the width of a small laptop screen: enough for code, a chat or a browser.
- A wide center with narrow sides (25 / 50 / 25 means 960 / 1920 / 960) keeps the window you work in straight in front of you, in the middle of the curve.
- The layout in the demo above: notes on the left, code in the middle, and the right column split into an AI chat over a terminal.
- At the default 2560 × 1080, thirds are only 853 points wide. Two halves of 1280, or 640 / 1280 / 640, fit better.
- At native 5120 (1×), thirds are about 1707 points each, if the small text doesn’t bother you.
For other ultrawides, see ultrawide monitors on a Mac and the monitor pages.
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 LG.
- 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 LG keeps its own layouts, and you can have several and switch from the menu bar. If your MacBook sits next to it, the laptop screen has its own zones, and when you unplug the LG its layouts wait for it until you plug it in again.
Questions
Does the LG 45GX950A work with a MacBook Pro?
Yes, over one USB-C cable that also charges it. Owners report “looks like 3840 × 1620” at 100 Hz on an M1 Pro and at 165 Hz on an M3 Pro. M5 Pro owners on macOS 26 lost both over USB-C; the HDMI port or macOS 27 brings them back.
Does the 45GX950A work with a Mac mini or a MacBook Air?
Apple says the M4 Mac mini drives one display up to “8K at 60Hz or 4K at 240Hz over Thunderbolt or HDMI” (Apple), the M1 and M2 Air one display up to 6K at 60 Hz (Apple), and the M5 Air up to 5K at 120 Hz (Apple). So 5120 × 2160 at 60 Hz fits on all of them. We haven’t found an owner report of this monitor on a mini or an Air, so higher refresh rates there are unconfirmed. On a base M1, M2 or M3, sharp modes stop at 3072 points wide, so “looks like 3840 × 1620” isn’t available.
Can the 45GX950A charge my MacBook?
Yes. Its USB-C port delivers up to 90 W along with the picture (LG spec sheet).
Why does everything look so big on the LG 5K2K?
macOS starts it at “looks like 2560 × 1080”, a sharp mode that doubles everything. In System Settings → Displays → Advanced, turn on “Show resolutions as list” and “Show all resolutions”, then pick about 3200 × 1350 or 3840 × 1620.
Is the 45GX950B different from the 45GX950A on a Mac?
The 45GX950B is the newer sibling, but we haven’t confirmed what changed or how it behaves on a Mac, so don’t assume this page applies to it. Shoji works the same on either: you draw the zones per monitor, whatever the brand.
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