Use the iMac 2020 (27-inch 5K) as a monitor
Yes, the 27-inch 5K iMac from 2020 works as a full 5K monitor for another Mac. I've tested it with DisplayBridge, the app I develop, and it works perfectly over one Thunderbolt cable.
In short: the 2020 is the best-equipped 5K iMac and still runs the newest macOS, so it is the one model you should keep as a Mac rather than convert. If you only want to buy a 5K monitor, a 2017 model costs much less.
The iMac 2020 in facts
| Full name | iMac (Retina 5K, 27-inch, 2020), model number A2115 |
|---|---|
| Display | 5120 × 2880 pixels, 500 nits, wide color (P3), True Tone; optional nano-texture glass |
| Thunderbolt ports | Two Thunderbolt 3 (USB-C) ports on the back |
| Last macOS | macOS 26 Tahoe, Apple's last macOS for Intel Macs |
| DisplayBridge | Tested, works: full 5K at 60 Hz, with sound |
| AirPlay to Mac | Yes, it can receive AirPlay |
| Target Display Mode | No |
| Used price (eBay US) | Median $699; half of all working units sold between $490 and $875 |
What DisplayBridge is
DisplayBridge turns a Mac into a display for another Mac, over one Thunderbolt cable. Install the app on the iMac and on the Mac you work on, connect them, click Connect, and the iMac becomes a second display of that Mac, at the full 5120 × 2880 pixels and 60 Hz, uncompressed and with sound. Disconnect, and the iMac is your Mac again, with nothing changed. It costs $29 once after a free 7-day trial, and the iMac never needs a license.
What sets the iMac 2020 apart
The 2020 was the last and best-equipped 27-inch iMac. Compared with the 2017 and 2019 models, its screen adds True Tone, and it was the only one available with nano-texture glass, a matte finish that cuts reflections. It also has a 1080p camera, better microphones and speakers, an SSD in every configuration, and it still runs macOS 26 Tahoe, the last macOS Apple makes for Intel Macs.
As a monitor with DisplayBridge, it works exactly like the other 5K iMacs: install the app on both Macs, connect a Thunderbolt or 40 Gbit/s USB-C cable to one of the two Thunderbolt ports on the back, and click Connect. I've tested it, and the picture arrives uncompressed at the full 5120 × 2880 pixels and 60 Hz, with the sound on the iMac's good speakers. The step-by-step guide shows the setup with screenshots.
Keep it a Mac, don't convert it
A conversion kit can turn any 5K iMac into a plain monitor, but the 2020 is the model where it makes the least sense. A working unit is still worth about $700, it runs current macOS, and the kit would remove its logic board for good. On the 2020, the replacement adhesive strips also have to be trimmed to fit. With DisplayBridge, the iMac becomes the same 5K monitor over a cable and stays a Mac you can use or sell later.
Known weak points of the iMac 2020
The best-documented problem of the 2020 iMac affected models with the top graphics option, the Radeon Pro 5700 XT: thin white lines that flickered across the screen at random moments, even when the iMac was idle. Apple fixed it with an update to macOS Catalina 10.15.7, so it shouldn't appear on a current macOS. If you see lines on a 5700 XT model you are about to buy, walk away: the iMac's own graphics chip still drives its panel when it works as a display.
Some owners also report that the fan is audible at idle in a quiet room. It is worth listening for when you test one, especially if the iMac will stand close to you.
What a used iMac 2020 costs
Working 27-inch 5K iMacs from 2020 sold on eBay in the US for a median of $699 in the last three months; half of them went for between $490 and $875, and the top configurations for well over $1,000. That makes the 2020 the most expensive 5K iMac used. If you want to buy a 5K iMac only to use it as a monitor, a 2017 model gives you a display of the same class for about $280.
Before you buy one, go through the checklist on my iMac 2017 page: Thunderbolt ports, screen, Apple Account and Find My, company management (MDM) and firmware password. The 2020 iMac also has Apple's T2 chip, which supports Activation Lock: open About This Mac, then System Report, and check that the Hardware overview shows "Activation Lock Status: Disabled".
Prices: eBay US sold listings, condition "Used", July to October 2026, without listings for parts, damaged or locked units, and without sellers with no positive feedback. Checked on 11 October 2026.
Questions about this
Does the nano-texture glass make the iMac 2020 a better monitor?
It reduces reflections, which helps in bright rooms or next to a window. It was an optional upgrade when the iMac was new, so only some 2020 iMacs have it; you can tell by the screen's matte look, without the usual glossy reflections. With DisplayBridge, the picture is the same on both versions.
Should I convert an iMac 2020 into a monitor with a kit?
I wouldn't. It is the newest Intel iMac, it runs macOS Tahoe, and a working unit is worth about 700 dollars used. A conversion kit removes the logic board for good. With DisplayBridge, you get the same 5K monitor over a cable and keep a Mac you can still use or sell.
Can the iMac 2020 also be used with AirPlay?
Yes. It can receive AirPlay from another Mac, wirelessly and with a compressed picture. For everyday work at the full 5K resolution, DisplayBridge over a Thunderbolt cable gives a sharper picture with less delay.