virtualbox.org

Hi,

My host and guest OS are both Xubuntu 20.04.3. My host machine is running a 4k monitor. The machine has an Rx550 GPU, 2gb. The guest allows a max res of 2560 x 1440 under display settings.

Is there a way to get 3840 x 2160 resolution on the guest OS?

I use Virtualbox Version 6.1.26 r145957 (Qt5.12.8) with no host or guest extensions installed. I have alloted 128mb to video memory which is the max allowed limit.

tyrannasaur wrote:no ... guest extensions additions installed

This may be the problem. Guest Additions includes drivers for the Virtualbox video card, which may give full 4K resolution.

IMO, 4K is hard enough for a real graphics card. It's pushing it to expect virtual hardware to cope with that data bandwidth. I would expect problems.

If you must then I recommend maxing the graphics RAM out to 256MB, that gives something like 8 frames worth of frame buffers. Hopefully enough.

What I would recommend is to choose a combination of smaller size and little scaling to make a bigger window.

Hi, with Guest additions installed the highest option has not changed.

128mb memory is the maximum allowed option, i can not use a higher value.

Start the VM from full power off, not save-state. Run until you see the problem happen, then shut down the VM from within the VM OS if possible. If not possible, close the Virtualbox window for the VM with the Power Off option set.

Please right-click the VM in the main Virtualbox window's VM list, choose Show Log. Save the far left tab's log, zip the log file, and post the zip file, using the forum's Upload Attachment tab.

tyrannasaur wrote: 128mb memory is the maximum allowed option, i can not use a higher value.

If 3D acceleration is enabled - which it had better be if you want to work at 4k - then the maximum is increased to 256MB.

mpack wrote:If 3D acceleration is enabled - which it had better be if you want to work at 4k - then the maximum is increased to 256MB.

AFAIK, this is only true for Windows guests. Create a Linux guest and try to set it yourself.

PS: You can trick the VirtualBox Manager, but that's left as an exercise for the reader.

AFAIK, this is only true for Windows guests. Create a Linux guest and try to set it yourself.

I already have several Linux guests. E.g. from a Manjaro guest :- I don't remember having to pull any unusual tricks to max out the graphics RAM.

mpack wrote:I don't remember having to pull any unusual tricks to max out the graphics RAM.

Did you create perhaps create your Linux guests with an older version of VirtualBox? I don't remember when the behavior of the VirtualBox Manager was changed, but it was either for 6.1.x or for 6.0.x.

If I create a new VM using the VirtualBox Manager 6.1.26 and select Linux as the guest OS Type, I cannot get the maximum value of the slider to change later on (except by temporarily changing the guest OS type, that is ). As soon as the Video Memory is set to 256 MB, the VirtualBox Manager will let you keep it.

My VirtualBox info:

VirtualBox Graphical User Interface Version 6.1.26_Ubuntu r145957
© 2004-2021 Oracle Corporation (Qt5.12.8)

I just enabled 3D Acceleration. I tried each of the three graphics controller options. In each case, 4k resolution in the host was not an option,

Doing these tests, I never saw the option to raise video memory above 128mb.

Hoping there's something else I can try. I'm even willing to buy a better video card if you guys believe it may help. I have an Rx550 with 2gb RAM

tyrannasaur wrote:Doing these tests, I never saw the option to raise video memory above 128mb.

Don't get sidetracked by our 256 MB discussion. I don't think that it's relevant here at all.

First of all, you should provide a (zipped) VBox.log file as was already requested in Re: 4k on Ubuntu guest?.

fth0 wrote: Did you create perhaps create your Linux guests with an older version of VirtualBox?

I don't believe so. My interest in Manjaro is quite recent, certainly from the VirtualBox 6.1.x era.

tyrannasaur wrote:My VirtualBox info:

VirtualBox Graphical User Interface Version 6.1.26_Ubuntu r145957
© 2004-2021 Oracle Corporation (Qt5.12.8)

I just enabled 3D Acceleration. I tried each of the three graphics controller options. In each case, 4k resolution in the host was not an option,

"6.1.26_Ubuntu" indicates the Ubuntu fork. We don't support forks here. Please install the real thing, not any of the tribute versions.

Do not "try each of the three graphics controller options". Only one is the correct choice for a Linux guest, that being VMSVGA. But to get the benefit you do of course need to enable 3D acceleration and install up to date Guest Additions. Provide the VM log requested and we'll see if you already did that.

If I install the real virtualbox, will it be able to use my current guest OS, or is it likely I'll have to start over?

We can't say anything about forks with certainty, but others who have done it were able to continue using their existing VMs.