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Is there a way to slow down virtual machine, and I don't mean limiting cpu resources, or such
but a real simulated slow down, which would also slow down system time so each virtual millisecond in vm would take preselected amount of real time milliseconds (e.g. 1 msec in vm would last 10 msec real time)

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What would be the end goal for this? – Kruug Jul 18 '13 at 20:29
At which point should it exactly slow down? before/at boot? – superuser0 Jul 18 '13 at 20:37
research into effects of time variance and how it might affect hardware, operating systems and software. ideally on the fly changes using slider/input box, but if nothing else even static value before or at boot time would be helpful – guest Jul 18 '13 at 20:45
Are you planning to place one computer in a temporal anomaly or something? Last I checked time runs at the same speed everywhere. If you are wondering what what happens if the clocks between two PC's are different, I suggest setting the time manually? – David Jul 18 '13 at 21:40

VirtualBox has a built in feature for this that you can run through VBoxManage, if you want to double the speed, browse to your VirtualBox folder from command prompt and run:

VBoxManage setextradata "VM name" "VBoxInternal/TM/WarpDrivePercentage" 200

Likewise, if you want to set the speed to 10%:

VBoxManage setextradata "VM name" "VBoxInternal/TM/WarpDrivePercentage" 10

Note that you should turn off any clock syncing mechanism such as NTP if you do this.

Source: Virtualbox Manual

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Just the fact that it's called WarpDrivePercentage says something about who'd want to use this... :) – Michael Kjörling Jul 18 '13 at 21:51
Now I really want to try this and just see what happens... – nhinkle Jul 18 '13 at 22:39

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