I have a MacBook Air M2 and a Lenovo IdeaPad S340 running Fedora Linux. I'm using Barrier right now to share mouse and keyboard between the two but I wish to use the Lenovo laptop as a secondary display for my MacBook Air.

The results on the Internet say that I could use a VNC server which I would not prefer as it will be very laggy or using a video capture card which I do not have. Any support will be appreciated.

  • Welcome to Ask Different! Questions must demonstrate a reasonable amount of research & understanding of the problem being solved. Please edit to either a) clearly describe your problem and the research done so far to solve it or b) include attempted solutions plus why they didn't work. In either case, be sure your expected results are clearly presented.
    – Thinkr
    Commented Jun 11, 2023 at 10:44
  • @Thinkr I have already described the problem and the research but the solutions are not to my liking that's why I'm asking here
    – Chris5112
    Commented Jun 11, 2023 at 10:51
  • 1
    Which specific solutions did you find, how did you apply them? You write "will be very laggy", did you actually try?
    – nohillside
    Commented Jun 11, 2023 at 10:55
  • I completely agree with nohillside's comment. Also, have a look at this question: apple.stackexchange.com/q/307356. It has been closed because being off-topic. Your question is basically the same, isn't it?
    – Thinkr
    Commented Jun 11, 2023 at 10:58
  • I have a kinda slow wifi connection so I think it'll be laggy..
    – Chris5112
    Commented Jun 12, 2023 at 14:39

1 Answer 1


…I wish to use the Lenovo laptop as a secondary display for my MacBook Air.

Buy a proper monitor.

The reason being is that the cost (time, work, and money) you’d have to spend to get even a mediocre experience eclipses the cost of procuring a second monitor.

The results on the Internet say that I could use a VNC server which I would not prefer as it will be very laggy…

VNC by nature, is slow.

Yes. VNC is a horrible protocol. It literally transmits the entire frame buffer (compressed) over the connection. The less bandwidth, the worse it gets. I’ve attempted to use VNC on a private LAN subnet with little to no traffic only to throw up my hands in frustration. I found it easier and faster to literally walk across a campus to sit in front of a Mac rather than try and use VNC.

RDP (Windows Remote Desktop Protocol) is hands down a superior protocol but it still lags significantly. This protocol essentially only transmits the changes within the frame buffer, not the whole thing. It was designed from the onset to be something that could function well on low bandwidth connections.

An super efficient alternative to RDP is Citrix ICA where you could get LAN type throughput over a 28.8 Kbps modem connection. The downside is it’s (was) very expensive.

You’re traversing a software and network stack

The reason for this lag is that you’re taking the contents of a frame buffer, either the whole thing or just the updates, compressing them, packetizing them, routing them over something, reassembling them then moving them into a local frame buffer for display. That takes time no matter how you slice it.

Bottom Line…

Can you do this? Sure. It makes a great side project. Is it feasible? No. As you searched and already found, sharing/extending screens is laggy and troublesome. Even with fully native solutions (Mac to Mac/iPad) with tools like SpaceDesk or Apple’s Sidecar, the connection still lags. I’ve personally used SpaceDesk and after the first couple/three times, it’s gathering digital dust in my Apps folder in favor of a dongle and proper monitor.

If you want a second monitor, get a second monitor.

VNC uses the RFB (Remote Frame Buffer) protocol. It’s an old protocol and hasn’t been updated since 2011.

  • Even though your post sounds fair, it does not answer the question. "Buy a second monitor" is not the answer to "Using a linux laptop as a secondary screen for my MacBook Air m2 without vnc (preferably wired)". There could be and will be reasons that you don't have in mind (maybe this laptop is mounted permanently to a wall for whatever reason) so people looking for an answer to this question will get left with "buy a second monitor". Commented yesterday

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