Why do both external monitors show the same thing on my Mac?

Because the hub is passing DisplayPort straight through from the laptop's USB-C port, and macOS does not split that single stream into two independent desktops the way Windows does. It is a platform limitation, not a broken hub. Anker states it on the product page for its Nano USB-C Hub (8-in-1, Dual Display): due to macOS limitations, only one external monitor can show different content, and both external monitors will display identical content.

What is DisplayLink and how is it different?

DisplayLink compresses the video on the computer in software and sends it over the USB data lanes instead of a native DisplayPort stream, then a chip in the dock decodes it back to a display signal. Because the operating system sees each screen as a normal display device, macOS will extend rather than mirror. The price is a driver install and some CPU load.

Which dock drives three displays from a MacBook?

The Anker Prime DL7400 Docking Station (14-in-1, Triple Display, DisplayLink) at $299.99 on anker.com is built for exactly this. Anker lists support for MacBook models with M1 through M5 chips, 140W upstream charging and 10Gbps data, and states that both macOS and Windows require installing the free DisplayLink driver.

Does DisplayLink need screen recording permission on a Mac?

Yes. Anker's own page notes that on macOS the DisplayLink Manager app requires screen recording permission to enable extended displays, and that Synaptics, which makes the DisplayLink chips, confirms no data or images are ever recorded or saved. If your employer's device management blocks that permission, a DisplayLink dock will not extend your displays.

Is a native DisplayPort Alt Mode dock better if my machine supports it?

For a single external display, yes. Native DP Alt Mode has no driver, no CPU overhead and no compression, so it is the better path when your computer can drive the displays you want on its own. DisplayLink is the workaround you buy when the host cannot, most often a MacBook that needs a second or third extended screen.

Why Your Second Monitor Mirrors on a Mac: DisplayLink vs DP Alt Mode Docks

A $35.99 dual-HDMI hub will mirror both screens on a Mac, and that is not a defect: Anker prints the limitation on its own spec sheet. DisplayLink docks such as the Anker Prime DL7400 route around it with a driver and drive three displays from a MacBook. Which one you need, and the tradeoffs.

Published: September 7, 2026 Updated: September 7, 2026 GadgetHub Editorial

Disclosure: this article contains affiliate links (Amazon Associates and impact.com). We earn a commission if you buy through them, at no extra cost to you. Prices are the figures shown on anker.com and us.ugreen.com on September 7, 2026 and change often. Specifications are manufacturer-published. We have not tested this hardware ourselves.

You bought a hub with two HDMI ports. You plugged in two monitors. Both are showing the same thing, and no amount of clicking in Displays settings will separate them.

The hub is not broken. On a Mac, a hub that passes DisplayPort through from the laptop’s USB-C port cannot hand macOS two independent desktops, and the manufacturer says so in the fine print. Anker’s spec note for its Nano USB-C Hub (8-in-1, Dual Display), $35.99, reads: due to macOS limitations, only one external monitor can show different content from the laptop, and on macOS both external monitors will display identical content.

There is exactly one way around this, and it is a different category of product.

The two ways video leaves a USB-C port

DisplayPort Alt Mode is the native path. Your computer’s USB-C port carries a real DisplayPort signal on some of its wires, and the dock simply routes that to an HDMI or DisplayPort connector. No driver, no compression, no CPU cost. How many independent displays you get is decided entirely by the host computer, not by how many video ports the dock has.

DisplayLink is the software path. A driver on the computer compresses each display’s image and pushes it through the ordinary USB data lanes; a chip inside the dock decompresses it and outputs a video signal. The operating system treats each screen as its own display device, which is why it extends instead of mirroring. You pay for that with a driver install and some processor load.

This distinction is why two docks with identical port lists can behave completely differently on the same laptop.

What each path costs on a desk in 2026

Product	Price (Sep 7, 2026)	Video path	Displays on a Mac
Anker USB-C Hub (7-in-1)	$25.99	DP Alt Mode	One extended
Anker Nano USB-C Hub (8-in-1, Dual Display)	$35.99	DP Alt Mode	Two, mirrored only
UGREEN Revodok Pro 7-in-1 with 4K DisplayPort	$40.99	DP Alt Mode	One extended
UGREEN Revodok Pro 10-in-1 Docking Station	$59.99	DP Alt Mode	One extended
Anker Nano Docking Station (13-in-1, Triple Display, removable hub)	$149.99	DP Alt Mode	Depends on host
UGREEN USB-C Docking Station, 3 Monitors 4K	$159.99	DP Alt Mode	Depends on host
Anker Prime DL7400 (14-in-1, Triple Display, DisplayLink)	$299.99	DisplayLink	Three extended
UGREEN Revodok Maxidok 10-in-1 Thunderbolt 5	$229.99	Thunderbolt	Depends on host
Anker Prime TB5 Docking Station (14-in-1, 8K)	$399.99	Thunderbolt	Depends on host

Two things stand out. The cheap dual-HDMI hub and the $299.99 DisplayLink dock are not competitors at different budgets; they solve different problems. And a Thunderbolt dock is not automatically the answer either, because Thunderbolt still delivers native DisplayPort streams whose count the host decides.

The DisplayLink dock, and the four things to know before buying

The Anker Prime DL7400 Docking Station (14-in-1, Triple Display, DisplayLink) is $299.99 on anker.com and is the mainstream answer for a MacBook that needs more than one extended screen. Anker’s published details:

Supports MacBook models with M1 through M5 chips, plus Windows
140W upstream charging to the laptop and 10Gbps data
Both macOS and Windows require installing the free DisplayLink driver
On macOS, the DisplayLink Manager app requires screen recording permission to enable extended displays; Anker notes Synaptics confirms no data or images are ever recorded or saved

That third and fourth point are the real buying criteria. A DisplayLink dock is a driver-dependent device. If your work laptop is managed and screen recording permission is blocked by policy, the dock will connect, charge and pass data, and still refuse to extend your displays. Check that before you spend $299.99.

The CPU cost is the other tradeoff. Compressing three displays’ worth of pixels in software is real work, and it lands on the same processor running your video call. For text, spreadsheets and browsers this is invisible on a modern machine. For colour-critical work or full-screen video on the DisplayLink screens, native is better.

Check the Anker Prime DL7400 on Amazon

When you do not need DisplayLink at all

Reach for a native dock, and save the money, in these cases:

One external display. Every hub in the table above does this without a driver. A $25.99 seven-port hub is enough.
A Windows laptop with two displays. Windows handles multi-stream transport, so a dual-output DP Alt Mode dock genuinely extends. The same $35.99 Anker hub that mirrors on a Mac extends on Windows.
A desktop Mac with enough ports. If the machine already drives your monitors directly, a dock is a port expander, not a video device.

For that middle case, the sensible buys are the UGREEN USB-C Docking Station, 3 Monitors 4K, at $159.99 or the Anker Nano Docking Station (13-in-1, Triple Display) at $149.99. Both are native docks with three video outputs, and both are honest purchases on Windows.

Check the UGREEN triple-monitor dock on Amazon

Check it on UGREEN.com

The mistake that costs $40

The most common version of this error is buying a hub because it has two HDMI ports, on the assumption that two ports means two desktops. Port count is a connector count, not a capability. We made the same point about data ports in our dock or hub guide: the Anker Prime Charging Docking Station (14-in-1, Dual Display, 160W) at $269.99 has five USB-A ports, and three of them run at 480Mbps.

Read the video row on the spec sheet, not the product name. If it does not say DisplayLink, and you are on a Mac, assume one extended display.

What we would buy

One monitor, any platform: Anker USB-C Hub (7-in-1), $25.99, or UGREEN Revodok Pro 7-in-1, $40.99
Two monitors on Windows: Anker Nano USB-C Hub (8-in-1, Dual Display), $35.99
Two or three extended monitors on a MacBook: Anker Prime DL7400, $299.99, after confirming you can grant screen recording permission
A Thunderbolt machine that already drives its displays: UGREEN Revodok Maxidok 10-in-1 Thunderbolt 5, $229.99, bought for bandwidth and ports rather than for extra desktops

Check the Revodok Maxidok TB5 on UGREEN.com

The honest summary: DisplayLink is a workaround, and workarounds have costs. Buy it when the host cannot do what you need, not because it appears higher up the product page.

Sources

All prices are store prices captured on September 7, 2026 and will change. Compatibility statements are the manufacturers’ own. We have not measured any of this hardware.

Frequently Asked Questions

Q: Why do both external monitors show the same thing on my Mac?: A: Because the hub is passing DisplayPort straight through from the laptop's USB-C port, and macOS does not split that single stream into two independent desktops the way Windows does. It is a platform limitation, not a broken hub. Anker states it on the product page for its Nano USB-C Hub (8-in-1, Dual Display): due to macOS limitations, only one external monitor can show different content, and both external monitors will display identical content.
Q: What is DisplayLink and how is it different?: A: DisplayLink compresses the video on the computer in software and sends it over the USB data lanes instead of a native DisplayPort stream, then a chip in the dock decodes it back to a display signal. Because the operating system sees each screen as a normal display device, macOS will extend rather than mirror. The price is a driver install and some CPU load.
Q: Which dock drives three displays from a MacBook?: A: The Anker Prime DL7400 Docking Station (14-in-1, Triple Display, DisplayLink) at $299.99 on anker.com is built for exactly this. Anker lists support for MacBook models with M1 through M5 chips, 140W upstream charging and 10Gbps data, and states that both macOS and Windows require installing the free DisplayLink driver.
Q: Does DisplayLink need screen recording permission on a Mac?: A: Yes. Anker's own page notes that on macOS the DisplayLink Manager app requires screen recording permission to enable extended displays, and that Synaptics, which makes the DisplayLink chips, confirms no data or images are ever recorded or saved. If your employer's device management blocks that permission, a DisplayLink dock will not extend your displays.
Q: Is a native DisplayPort Alt Mode dock better if my machine supports it?: A: For a single external display, yes. Native DP Alt Mode has no driver, no CPU overhead and no compression, so it is the better path when your computer can drive the displays you want on its own. DisplayLink is the workaround you buy when the host cannot, most often a MacBook that needs a second or third extended screen.