I created a Windows 10 Virtualbox VM on Windows 10 host. Also installed the Guest additions. The machine runs fine on the Windows host. However, on the Ubuntu 18 host runs ridiculously slow, ya know, can't even use it. Both hosts are running Oracle Virtualbox 5.2. Google reports tons of "Virtualbox slow" cases but none has helped me solve this particular problem scenario. Again, same Windows 10 guest VM, runs fine on Windows 10 but sloow on Ubuntu 18.

  • Guest addition should match version of VirtualBox on host(!!!) – Alex Aug 27 '18 at 7:29
  • That is my understanding as well. I installed the addition by first selecting "Devices->Insert Guest Additions CD Image" and then rolling on with the installation from the virtual CD drive. Btw. the CD drive shows "VBox GAs_5.2.18" which is exactly whatIy have on the host. – Ya. Aug 27 '18 at 13:43
  • Make sure you enabled in BIOS virtualization support as well set VT-x, nesting pages in VirtualBox and enable 2D (only) video acceleration, also give Win10 guest at least couple of gigs of RAM – Alex Aug 27 '18 at 15:40
  • Enabled 2D video acceleration (both 2- and 3D were disabled) but no difference. Hardware acceleration (as reported by BIOS) as well as VT and Nested paging were already enabled. The gues has 2GB, both hosts have 8GB. Also tried giving 4GB to the guest but it seems to have made things even worse (hard to tell but definitely not better). – Ya. Aug 27 '18 at 19:31
  • Try to remove completely anything related to virtualbox from Ubuntu and reinstall it from official ubuntu's repository, ubuntu usually ships a little outdated version but as you said you have latest 5.2.18 which is kinda strange. If you installed VB from virualbox site then before doing that you need remove completely everything related to virtualbox from ubuntu before doing this. – Alex Aug 27 '18 at 19:40

I think your problem is not related to your own setup (hw/sw), but more like an issue in Ubuntu/Xubuntu itself. I've also observed a huge slowdown when switching from Ubuntu 16.04 to 18.04 and virtual machines performance too.

I used virtual Windows 10 for testing there along with Ubuntu 18.04 as a host, and I've noticed that it happened after some package updated in Ubuntu. It's definitely not related to the kernel (I even tried the latest Linux kernel 5.0), but some component inside Ubuntu itself. What's more interesting, is that I feel it's related to ... video driver/emulation. No, I'm not kidding, because even my host also became slower.

What I could suggest you would be to compile own video driver in Ubuntu and see the results. I'm a bit old and remember how it looked like in Windows 95/98 when you didn't have video driver installed at all.

Eventually, you may monitor disk and CPU usage in Ubuntu. iostat command comes with systat package (sudo apt install sysstat), so if you ran it with iostat -m 2, it would show you how many bytes are read/written to disk in the host machine.

Additionally, please make sure you're running your CPU at full speed. It's a long story, but you can see your current CPU speed with a package called i7z (sudo apt install i7z). It will show you whether it's running at full speed (i.e. 2.3GHz or throttling is active and runs at - let's say - 800MHz).

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.