I recently bought a maxed out iMac 5k (2019). I thought I would have some fun and start my software development project using Ubuntu via VirtualBox.

Here is a screenshot of my VirtualBox configuration:

Virtualbox Configuration

So pretty much I made this post to mention... that when I maximize the window and set the scaling factor to 200%, the performance is horrible. Is this to be expected?

When I type the text significantly lags behind and there are often multiple repeated keystrokes (for example, I'll get hhhhheeeelllllooooooo) if I tried to type "hello."

When I set the resolution to something much lower within Ubuntu such as 2560 x 1600, the performance is awesome, but now my window is tiny relative to the actual screen of my iMac.

Am I missing some key configuration or were my expectations of running Linux in a virtual environment with high performance too high?


  • Set your CPU and memory specs down... 2 CPU's and 2048 memory. See if that improves things. If it does, I'll write a formal answer that you can accept. Report back. Start comments to me with @heynnema or I'll miss them. – heynnema Sep 4 '19 at 23:52
  • And assuming that you've properly installed Guest Additions, you can eject the GA CD image. – heynnema Sep 4 '19 at 23:57

After scouring the internet, I found this link: https://forums.virtualbox.org/viewtopic.php?f=8&t=90446&start=60

Pretty much Virtualbox does not play nice with iMac's hiDPI resolutions.

Per the link above, I installed this piece of software: https://github.com/avibrazil/RDM

And set my resolution to a non hiDPI resolution. Now the performance of my Ubuntu VM runs great!

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