[Solved] Poor performance under Windows host versus Linux host

[Super-chemist]

Hello everybody
Please excuse my spells, english is not my native language.

I try to run VirtualBox on an old DELL VOSTRO 3560 with a i5-3210M CPU (dual core 2.5GHZ with intel VT-x).
This computer is from 2012 but still runs good since I added an SSD in it and 8GB of RAM.

In 2016, I played with VirtualBox 5.1.10 and several linux iso under my Windows 7 host.
At that time, the computer had an old HDD and 4GB of RAM, and Virtualisation runs pretty well with Ubuntu LTS 16.04 as a guest.
I then stop "playing" because of my family life...

Now in 2019, I wanted to play again.
So I installed the new VirtualBox 6.0.8 and get the last Ubuntu 18.4 LTS iso.
The host is the same except that:
- I formatted and reinstalled Windows a couple of time
- I put an SSD in place of the old HDD
- I gave it 8GB of RAM
The problem is that the guest is incredibely slow.
Intel VTx is activated in the host BIOS (I checked twice) and in VirtualBox configuration.
The guest is so slow that I can't even install Ubuntu in the virtual HDD!

I tried also this configuration:
- Windows 7 host
- old 5.1.10 VirtualBox that used to work
- old 16.4 ubuntu iso that used to work
The problem is the same, the guest is so slow that I can't use it.

I then tried this configuration on the same hardware:
- Ubuntu 18.4 host, up to date (installed on multiboot on the SSD)
- VirtualBox 5.2.18 as packaged in Ubuntu repos (sudo apt install virtualbox)
- Ubuntu 18.4 iso as a guest
Surprisingly, the virtualisation is then quite fast, as it was in my memories in 2016.

I don't see any difference between the params on my two hosts, neither in VirtualBox params nor in the specific VM params (which I left default for the sake of debug).

I guess there is a little different parameter between my two hosts configurations, but I have no idea where to seek...

I send you the logs of the Windows 7 host

WIN7HOST-slow.zip

Logs of the windows7 host when it is so slow

(47.59 KiB) Downloaded 28 times

.
Logs of the Ubuntu host will come in a few minutes in another message, reboot needed.

Thanks for your help

[Super-chemist]

And here is the log under Ubuntu 18.4 host:

UBUNTU-host.zip

Logs of the Ubuntu host when it is normally fast

(22.08 KiB) Downloaded 25 times

[mpack]

The only difference I can see:

On the Windows host you assign 100% of available CPU cores to the VM, leaving nothing for the host OS and VirtualBox itself to run on.

On the Linux host you do not make that error.

[Super-chemist]

Hello mpack
Thank you for your help.

You are right about the number of virtual CPU, it's a difference I made when trying to resolve my problem.
Thus, my VM aren't in a high load, so I never noticied a problem having 2 virtual CPU on my dual core system...

My VM is now set with 1 virtual CPU, and the problem still occurs.

Is it possible that a windows driver in the host causes this problem?
Something related to a vt extension not working...
I have the feeling that things are emulated by software under windows host, and emulated by hardware under ubuntu host...

Even loading the grub menu of the ubuntu iso is laggy under windows, and not under ubuntu host!

[mpack]

It's hard to say anything more than I have, since the Windows logs were grabbed while they were still open for writing, hence they are only partial.

[socratis]

I think that your antivirus on your Win host is the one that's slowing you down:
[quote=""VBoxHardening.log""]

1f34.1ff8:     ProductName:     Avast Antivirus 
1f34.1ff8:     FileDescription: Avast VM Monitor
1f34.1ff8:     FileDescription: Avast Virtualization Driver
1f18.13b8:     FileDescription: Avast File System Minifilter for Windows 2003/Vista

[/quote]
Completely uninstall it (don't simply disable it) and try again. And of course lower the CPUs to 1, following mpack's advice.

[Super-chemist]

Hello

I've tried to uninstall my antivirus, and it works!
You're right, it's Avast that slow down the VM.

Since I don't want to let my computer without antivirus, I reinstalled Avast and tried many exceptions and/or disables, but can't find a way to make Avast and VirtualBox cooperate.

Do you advice another antivirus?
If not, you can set my topic as [solved]

Thanks

[mpack]

Since I expect Microsoft to have a better understanding of Windows Internals than Avast, as well as the ability to tweak those internals to aid performace: I would expect the Microsoft Windows Defender suite to be adequate. It's the only thing I would ever use on Windows 10 hosts. I went directly from XP to Win10 so I can't really say that Avast is equally unnecessary on Win7, but I'd be surprised if wasn't.

[socratis]

Do you advice another antivirus?

The last time I used an antivirus it was more than a decade ago (actually more than 15 years), and I decided that it was more of a burden than a solution. Since then, the only thing I've used is the built-in ones. On all my hosts/guests...

If not, you can set my topic as [solved]

I would mark it as [Solved] in any event, because we've solved the apparent slowness of your VM. Not your antivirus worries though...