Lower resolution on linux guest than on the windows host

[ohnoplus]

Host: Lenovo thinkpad T470s running windows 10.
VirtualBox: Version 5.1.28 r117968 (Qt5.6.2)
Guest: Xubuntu Linux 16.04 with guest additions installed using the guest additions cd image.

On my linux guest the screen resolution looks substantially lower in resolution than on my host display. You can see pixels, in the text and icons and similar. On the host, everything looks nice and high resolution. I've set 3d video acceleration on and off, with the same general effect. Screen scale factor is set at 100%. I have a screenshot of my guest running in a window on my host. If your screen resolution is good enough and you zoom in some you can maybe see the difference. Any suggestions?

[mpack]

Sounds like you have scale mode enabled. See user manual section 1.8.5.

[ohnoplus]

Thats a great guess @mpack. I should have clarified that, in this case though, scale mode is off. I can make things look worse by turning it on. Auto-resizing is on though. Picking other screen resolutions manually also doesn't seem to help. The problem also persists if I try to run in seamless mode.

One additional bit of information. I only have this problem when I run the laptop as a laptop. I also have a docking station, which, when I connect my computer to a docking station and look at the virtual machine with a regular monitor everything looks fine. A few other odities:

1) The icons in the virtualbox manager (even when the virtualbox is off) also appear to be somewhat grainy on the laptop screen (but not the host).
2) The icons and text both within the virtualbox, as well as the virtualbox manager look a lot smaller when I connect to the docking station, than they do on the host.

Any other ideas?

[socratis]

Any chance of including a screenshot of what you mean exactly? I do not need your full 2880x1800 screen, just a small corner where the problem can be seen.

[ohnoplus]

Pardon the delay. Here's what things look like on my regular monitor:

External monitor with better resolution

ExternalMonitorVbox2.PNG (5.82 KiB) Viewed 3396 times

And here is how they look on my laptop monitor:

LaptopMonitorVbox2.PNG (7.97 KiB) Viewed 3396 times

I realize its hard to do an apples to apples comparison because the icons are a lot smaller on the External monitor, but thats what I would prefer, small and sharp icons, even on the laptop screen, as seen below for the windows host:

WindowsLaptop.PNG (5.34 KiB) Viewed 3396 times

[socratis]

Any chance that you have a HiDPI display?

[ohnoplus]

Good question @socratis. This is a lenovo T470s. They don't call it HiDPI; rather they call it WQHD display. Perhaps it is the same thing?

[BillG]

2560x1440 ?

[ohnoplus]

Windows seems to think it is 1920x1080 when I open "change my screen resolution" from the start menu.

[socratis]

So does mine (1920x1200 to be exact), but it's actually sitting on a 2880x1800 MacBookPro retina (HiDPI). So check your host's settings. Oh, and check the HiDPI option in the VM settings, Display.

[ohnoplus]

Thanks! I can't seem to figure out how to do either of those things. I realize monkeying with host screen resolution is outside of the purvey of this forum, but here's what I see when I try to change the host resolution. I don't see any options for going to a higher resolution.

WindowsResolution.PNG (33.03 KiB) Viewed 3364 times

Also I don't seem to have any trouble viewing things on the host display in the first place.

Under VM settings, display, I see this window. I don't see any options relating to HiDPI. Am I missing something?

WindowsResolution.PNG (33.03 KiB) Viewed 3364 times

Thanks for bearing with me on this.

[socratis]

I'm afraid I can't help you with your Windows host/guest HiDPI settings as I only have a Mac and they work differently. But I would also look at Lenovo's support sites for related info.