virtualbox.org

Hello !

I am in a fight for optimum guest display resolution.
I have my WinXP VM under Win10 host, native screen resolution is 1920x1200. VBox is 5.0.12 with extensions pack installed.
Whatever I try, the resolution (read in "Display properties") of the guest display never goes above 1536x960 in full screen mode ; depending on my settings in "Preferences / display", the 1536x960 resolution is either at the end of the slider ("automatic") or someplace before ("none") and in this case the end of the slider offers me a 1600x1200 resolution which is the wrong aspect ratio.

I have used VBoxManage to effect the following changes :
- create CustomVideoMode1 with 1920x1200x24 resolution
- set GUI/MaxGuestResolution at 1920x1200

This has been useless as far as I can see ; but something funny happened : after a certain length of time and numerous boots of the guest, all of a sudden I had my guest resolution of 1920x1200 and simultaneously the GUI window had become smaller with clean cut fonts instead of blurry.
I thought the problem was solved, but later and after a host shut down and reboot the situation was again the same.
I played at disabling display scaling @ high DPI for VirtualBox, the blurry GUI became clean again but no change in the guest screen resolution.

One last thing : I am using an imported GPU (host display adapter : Radeon R7 200).

Thank you to all of you for suggestions and help !

Solved !

But solved without knowing the true reason...
Here is what I did before the resolution on the guest screen became equal to native and the GUI panel became sharp :
- reset GUI/MaxGuestResolution at "any" (through command line, of course)
- set Chipset on ICH9 instead of PIX3
- increased System memory to 4 GB instead of 2 (my infrastructure has 16 GB RAM)
- set Processor on "4 CPU" because I had mistakenly left it on "1"
- kept VT-x and Nested paging checked as before
- display remained at 128 MB memory, 100% scale, as before, but I removed the 3D accel (kept 2D)
and... but this was a pure chance happening, Microsoft chose this moment for a major update of my Windows 10 !

So that I could only see one thing : it works ; on the guest panel I have the 1920x1200 resolution and, surprise, the desktop icons rearranged themselves to replicate their exact arrangement on the old computer.

Hope this can be useful to some of you.
I wish I could write [Solved] in the thread title, but do not know how to do it ; is it going to be done by a moderator ?