[Bug]: Duel 4k Monitors, Both have 3840 x 2160 Resolution

[deterset]

Version

7.2.6

Host OS Type

Windows

Host OS name + version

Windows 11 Pro Build 26200.7623

Host Architecture

x86

Guest OS Type

Windows

Guest Architecture

x86

Guest OS name + version

Windows 11 Pro Build 26100.7623

Component

Other

What happened?

Trying to use Full Screen on both monitors. I have tried with and without 3d acceleration, without success.
One screen is full screen with 3840x2160 resolution while the second will only allow 1920x1440 in the center of a 3840x2160 screen.
That's the best I've been able to get even using help from AI.

VBox.log

Windows 11 Pro.log

VBoxHardening.log

How can we reproduce this?

I am using the AMD Radeon(TM) Graphics on the motherboard.

Did you upload all of your necessary log files, screenshots, etc.?

• Yes, I've uploaded all pertinent files to this issue.

[deterset]

I found out today that in order to get 4k HR on both monitors the refresh rate need to be set at 30hz but Virtualbox has an issue with that and sets the 1st monitor to 60hz. This may not be a bug but just a limitation of VirtualBox.

[VP-at-oracle]

The guest refresh rate is irrelevant. If you host can display on both monitors then the guest should work too.

Could you please verify that the guest can use the 3840x2060 resolution in windowed mode? In order to do so: start guest in normal windowed mode, then disable menu item View/Auto-resize Guest Display in the VirtualBox VM window, then run the following command on the host:
vboxmanage controlvm "LVB Windows 11 Pro" setscreenlayout 0 primary 0 0 3840 2060 32 1 on 3840 0 3840 2060 32
You should get 2 guest windows with scrollbars and be able to open guest's Display settings to verify the guest resolution.

[deterset]

This works! slightly smaller than the host screens but defiantly more area to work with. If you need me to run more tests on this configuration just let me know. Thank you,

…

On 4/22/2026 1:55 PM, Vitali Pelenjow wrote: *VP-at-oracle* left a comment (VirtualBox/virtualbox#530) <#530 (comment)> The guest refresh rate is irrelevant. If you host can display on both monitors then the guest should work too. Could you please verify that the guest can use the 3840x2060 resolution in windowed mode? In order to do so: start guest in normal windowed mode, then disable menu item View/Auto-resize Guest Display in the VirtualBox VM window, then run the following command on the host: vboxmanage controlvm "LVB Windows 11 Pro" setscreenlayout 0 primary 0 0 3840 2060 32 1 on 3840 0 3840 2060 32 You should get 2 guest windows with scrollbars and be able to open guest's Display settings to verify the guest resolution. — Reply to this email directly, view it on GitHub <#530?email_source=notifications&email_token=AAH4KKLNQHKKBRIJ6INLOIT4XEBQJA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTIMRZHA3TGNRXGQ32M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L#issuecomment-4298736747>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAH4KKNZFKO5O5M6Q23Y7XD4XEBQJAVCNFSM6AAAAACUAS3OMCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DEOJYG4ZTMNZUG4>. You are receiving this because you authored the thread.Message ID: ***@***.***>

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