Guest Ubuntu 16.04 runs very slowly in VirtualBox Windows 10 host

Machine is 64-bit ACPI motherboard with i5 quad-core and 8 Gb of memory running Windows 10-Pro host. Monitor is Acer T232HL touchscreen. Video card is AMD Radeon R7 200.

Installed VirtualBox then created guest virtual machine with 2Gb of allocated memory and 200Gb of fixed virtual disk and 128 Mb of video memory.

Installed Ubuntu Desktop 16.04, then installed Guest Additions. 3D acceleration is checked and confirmed.

Guest machine is still painfully slow, with refresh errors leaving some menus blank.

Any suggestions?

Some general troubleshooting...

• Make sure Unity can use 3D acceleration - it makes a big difference. Run /usr/lib/nux/unity_support_test -p from the terminal and note whether the last line shows Unity 3D supported: yes. If not, enable it in the VM options.

• Check you have given it enough video memory. The default settings in VirtualBox for guests are pretty low. Give it 64MB at least, and 128MB if you can.

• Check screen resolution. No matter what hardware I try, it just can't seem to power my 4K screen at its native resolution (3840 x 2160). Significantly better experience at 1920 x 1080, scaled.

• Check CPU virtualisation settings. If you have, say, a 4-core CPU don't assign all 4 cores to the VM. If you do that, the VM guest will fight the host for resources and the result is that it will actually run slower. Stick to one or two cores. (There's not much difference between 1 and 2 in my experience, but yours may differ).

• Do the same for RAM as for CPU. Don't assign more RAM than you need - ensure the host has enough left for itself. 4GB for Ubuntu desktop seems fine for practically everything I throw at it.

• I've read that people get better speeds on a mechanical hard disk by using a fixed allocation virtual HDD rather than dynamic. In my experience there's no noticeable difference, but perhaps worth mentioning anyway.

I want to share what I figured out, and trust me it took me very long:

Ubuntu Unity likes a real graphics card, not virtual stuff from vmshare or virtualbox

It just doesn't work well in virtual box.

You can try all the stuff the other guy posted and it will be better, but not like you want it to be. Basically: don't waste your time.

Alternatively:

Use another distribution that does not use Unity as UI.

I've successfully used Lubuntu 14.04

Not 16.04, because I did it a couple years back. And I think Lubuntu changed their UI, so be warned.

Another option is to switch to Gnome, but that switch has to be done completely, without exception... ( Ubuntu will go back to gnome in 2018 anyway )

I remember trying something like that back when I had my problems, and it did not work well neither...

There SEEMS to be an option to uninstall it via this.

A friend of me is doing that just that right now. I will let you guys know about it.

Better:

Use an image that comes with a different UI engine. Gnome, KDE, Lubuntu are some examples that should work. Lubuntu works for sure, at least in 14.04.

EDIT:

So my friend tried out and said Lubuntu 16.04 does feel a lot faster and more native than his Ubuntu install. But instead of reinstalling everything on Lubuntu, he tried out switching to gnome and followed this guide (mentioned earlier).

He said that after switching to gnome and removing Unity, it feels a lot more native.

One for people landing from Google (rather than chronic sufferers):

I observed very poor performance having "slept" the Windows 10 host with the VM running. A VM reboot resolved the issue. Hope this helps someone.