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A 27-inch iMac alone on a dark stage under one spotlight, its screen switched off.

Give your 5K iMac an encore.

Encore5K turns a 27-inch 5K iMac into a sharp second display for your Mac. One cable, sound included.

Join the beta See how it works

5120 × 2880 pixels, still waiting for their cue.

Brilliant screen. Retired computer.

A 27-inch 5K iMac has a panel most monitors still can’t match: 5120 × 2880 pixels, wide colour and a finish you notice every day.

The computer behind it ages faster. Apps stop supporting it, macOS stops updating it, and a superb screen ends up in a cupboard.

Older iMacs could act as a display for another Mac. The 5K models never could.

The same iMac seen close up on the stage, its screen lighting up with a Mac desktop.
Drag me

Lights down.

And then it comes back on.

Encore5K adds a 5K display to your Mac and sends it down the cable. The iMac shows it full screen, pixel for pixel, and your Mac treats it like any other monitor.

Only what changes travels.

The picture is cut into 3,600 tiles of 64 pixels. When something moves, Encore5K sends just the tiles it touched, packed in a format the iMac’s graphics chip unpacks in hardware.

0 tiles this frame

Nothing moved, so nothing is sent.

Drag the window on the screen.Drag the window on the screen with your finger.

An illustration on the real 80 × 45 tile grid of a 5K screen, at 4 KiB a tile before LZ4 compression.

One cable between them.

Thunderbolt carries a 5K desktop with room to spare. A plain Ethernet cable straight between the two Macs works too, and if you plug in Thunderbolt later, the picture moves over by itself.

frames a second, scrolling a full-screen page of text
55
ms round trip, Mac to iMac and back
6.2
Mbit/s on a link that carries many thousands
440

Measured with an M4 Pro Mac mini and a 2019 27-inch iMac over Thunderbolt, encrypted.

Backstage

Run from your menu bar.

Encore5K lives in your Mac’s menu bar. One click shows which iMac is showing your Mac, over which cable, and how quickly the picture gets there.

Extend, or mirror.

Use the iMac as a second display at its full sharpness, or have it show the same picture as your main display. Flip the switch and it changes over in a moment, without reconnecting.

The Encore5K settings window, General section: streaming to iMac 27-inch over Thunderbolt Bridge, with Mirror main display switched off, so the iMac is an extra display.
The Encore5K menu bar panel: streaming to iMac 27-inch over Thunderbolt Bridge, 5120×2880 at 60 frames a second, 6 ms delay, showing the extended desktop.

Interval

The parts you notice later.

Sound

Your Mac’s sound plays from the iMac’s speakers, and the volume keys still work. Needs macOS 14.2 on the Mac.

Pairing

The iMac shows a six-digit code. Type it once on your Mac. Everything between them is encrypted from then on.

Plain words

No picture? The iMac tells you why: your Mac is asleep, streaming is paused, or the cable came out.

Updates

Update Encore5K on your Mac and the iMac updates itself the next time they connect.

Pointer

The pointer travels on its own connection, so it never waits behind a big frame.

Unplugged

Pull the cable and your windows wait on the virtual display for a minute, ready for it to come back.

Programme notes

Setting up

  1. Connect the two Macs with a Thunderbolt cable, or an Ethernet cable straight between them.
  2. Open Encore5K on your Mac and Encore5K Viewer on the iMac. They find each other.
  3. Type the six-digit code the iMac shows. The iMac then appears in your Mac’s Displays settings, ready to arrange, or switch on Mirror main display to show the screen you already have.

What it runs on

Your Mac
macOS 13 Ventura or later, Apple silicon or Intel. Sound needs macOS 14.2.
Your iMac
A 27-inch 5K iMac on macOS 10.15 Catalina or later. Built on a 2019 model; the beta is how we confirm the others.
The link
Thunderbolt for the best picture, or gigabit Ethernet, direct or through a wired network. Wi-Fi works in a pinch, but a cable is the point.
Limits
No HDR: 8-bit colour in Display P3. A mirror is scaled to fit the iMac, so extending is the sharpest. The iMac stays logged in while it’s a display.
Licence
A one-time purchase with a free trial. Price announced at launch.
Encore5K

Your iMac’s encore starts soon.

Encore5K is in beta. Tell us which Mac and which iMac you have, and we’ll send you the first builds as they’re ready.

Join the beta