Virtualbox 6 on dual E5-Xeon 8 cores each - poor performance

Discussions related to using VirtualBox on Windows hosts.

Virtualbox 6 on dual E5-Xeon 8 cores each - poor performance

Postby Frank Kodis » 15. Oct 2021, 23:19


I use VB on and off for years. I started form first version out of curiosity and it evolved into a tool that is actually extremely useful for me to test stuff out. Until now i always used slower single processor "gamer" computers and VB always worked, hm, accordingly but i never expected anything if comes to performance.

Now thou i bought a dual Xeon workstation with huge RAM and i cant find any solution to very poor performance of most guests i install on it. I found some info to not declare more than 2 processors for guest because something... somewhere else i found another piece of advice.. and another. And nothing really works.

I did multitude of tests and nothing really works. No matter of what number of Processors i declare in settings for guest machine it really never works like supposed to.

So, where is can find a exact info or piece of documentation about correct configuration that my guest machine would run with for example 6 cores and utilize as much power from host machine as needed? I dont mind to give VB all power available except whats needed for OS (Windows 10 x64) - using VB i never do anything power hungry or run such processes.

Thanks :)
Frank Kodis
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Joined: 15. Oct 2021, 23:01

Re: Virtualbox 6 on dual E5-Xeon 8 cores each - poor performance

Postby scottgus1 » 15. Oct 2021, 23:36

Let's look at a poorly-performing VM.

Start the VM from full normal shutdown, not save-state. Run until you see the problem happen, then shut down the VM from within the VM's OS if possible. If not possible, close the Virtualbox window for the VM with the Power Off option set.

Right-click the VM in the main Virtualbox window's VM list, choose Show Log. Save the far left tab's log and the hardening log next to it, zip them, and post the zip file, using the forum's Upload Attachment tab.
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Re: Virtualbox 6 on dual E5-Xeon 8 cores each - poor performance

Postby frg » 19. Oct 2021, 22:45

I am quite happy with 2 E5-2667v3 and 128GB. About 30% faster than the previous e5-2667v2 setup I used.

Disable hyperthreading. It did slow down things for me when doing compiles or other cpu intensive tasks.

Not knowing which hardware:
Make sure NUMA is activated in the BIOS
Make sure you never add more physical cores than one processor has. Doing otherwise will usually hang the vm during start.
vt-x and vt-d should be on too.

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