virtualbox.org

Hi,
this is specification of my host machine:

Laptop: HP EliteBook Folio 9480m
Processor: Intel(R) Core(TM) i5-4310U CPU @ 2.00GHz, 2601 Mhz, 2 Core(s), 4 Logical Processor(s)
RAM: 8.00 GB
OS: Windows 7 Enterprise
Virtual Box version: 5.1.0.r108711

As a guest OS, I use Ubuntu 16.04.3 LTS.
VM parameters:
Base Memory: 2.0 GB
Processors: 2
Acceleration: VT-x/AMD-V, Nested Paging, PAE/NX, Hyper-V Paravirtualization

Installed packages:
- Mozilla Firefox 55.0.2
- flashplugin-installer/xenial-updates,xenial-security 27.0.0.130ubuntu0.16.04.1 amd64

Problem description:
1. as only I open Web Browser guest OS slows down significantly
2. as only I load an web page containing flash, guest OS slows down dramatically. I can barely use guest OS/very slow response.

Seems that the bad performance is caused by flash plugin.
- Is this some well known problem in Virtual box?
- Does anyone experience similar problem?
- Is there any workaround for that?

Its really difficult to work with guest OS like that.

Well, I don't run linux guests, but according to the online documentation, the recommended paravirtualization provider for linux guests is "KVM," not "Hyper-V." You may want to change this to see if it results in improved performance in the Guest.

Second, you may want to check to see if 2-D and 3-D acceleration is properly enabled for the Guest. You will need to install the appropriate guest additions. Online documentation for that is also available.

Please provide a VM log file. With the VM fully shut down, right click it in GUI. Select "Show Log" and save "VBox.log" (ONLY) to a zip file. Attach the zip here.