Performance of NTVDM unacceptable

[CChrisA]

Linux host/WinXP sp3 guest

When running an old 16 bit visual basic application under ntvdm performance is unacceptable. The processor use never drops below ~30%.

When using the application performance is dreadful. Screen paints can be watched and any operation involving IO is stunningly slow.

Machine is a conversion of a vmdk, IO APIC still in use (though configured as such).

[Johan van Zijl]

Same problem here. Host is Vista x64 SP1. Guest is XP SP2(32bit). VirtualBox v1.6.4. When running 16bit application on guest ntvdm.exe utilizes 100% CPU on guest. Also, this is a brand new VM with no IO APIC enabled.

Maybe 64->32->16 is pushing it a bit.

[Sander van Leeuwen]

Without a VBox.log we can't say anything meaningful. Attaching the offending application would be useful too.

[proapps]

Installers that use ntvdm hang on WinXP host and guest on VBox 2.1.0. Examples: Office 97 and MSDN for Visual Basic 6 (I know they're legacy but I need them for development/support) - running setup.exe causes some disk activity for about 5 minutes then nothing, although ntvdm is in the process list at > 40% CPU usage. I'd be happy to provide a VBox.log file if someone would let me know where to find it.

[proapps]

Further to my post on 24 Dec 08, I found the following blog that discusses NTVDM performance issues on *native* Win2K and XP Prof. The issues and resolutions he describes might be usable by VirtualBox developers to resolve the NTVDM performance problem in vBox Windows guests:

​http://grandstreamdreams.blogspot.com/2008/07/windows-cpu-throttling-techniques.html

Note that the blogger says the performance issue didn't seem to arise on multi-core chips.

In my 24 Dec post I offered to send along a vbox.log file. If you let me know where I can find it I'll be happy to send it along.

Replying to sandervl73:

Without a VBox.log we can't say anything meaningful. Attaching the offending application would be useful too.

[Frank Mehnert]

Please open the VM selector and choose Machine / Show Log ...

[MARIADASSOU Romain]

Bug still here. No performance change for :

• Virtualbox 2.0.x
• Virtualbox 2.1.x
• Virtualbox 2.2.0

Hosts are Linux (64bits) and guests are Windows XP 32bits (SP2 / SP3) / Windows 2003 32bits (SP1 / SP2).

ntvdm always run very slowly if VT-X/AMD-V is not checked. If checked : no problem. ntvdm will always run very slowly on non capable VT-X/AMD-V machine.

Your challenger (vmware server) in version 1.0.x and 2.0.x are running ntvdm extremely fast.

[MARIADASSOU Romain]

Log of a MS2003 Virtual Machine on VBOX 2.2.2

[MARIADASSOU Romain]

Still here : No performance change for :

• Virtualbox 2.2.2.

NTVDM is still very very slow on a host not capable of hardware virtualization

[Dave Ulrick]

I've observed glacial performance of NTVDM-managed 16-bit Windows apps with a Linux 32-bit host and XP SP3 guest (without hardware virtualization) up through VBOX 3.0.10. Since upgrading to VBOX 3.0.12 I'm seeing good performance with 16-bit Windows apps run via NTVDM. Did a recent VBOX patch help, or has Microsoft lately issued any XP updates that might have helped?

[MARIADASSOU Romain]

I have just upgrade to 3.0.12 from 3.0.10. And I do not see any improve performance on my different guests.

Do you have all MS update ? Because, I have none if Service Pack only.

[Dave Ulrick]

Yes I do have all available MS updates installed.