Windows – Does VirtualBox support line in and the microphone

VirtualBox does not support adding more memory in this fashion. However, in many cases it will still be worth it to restart the computation, because the speed may increase by a factor of a hundred or more by using RAM as opposed to a hard drive.

An important note, even if your VM is "thrashing" that does not mean that the RAM is not getting used by windows (caching the disk that the VM is using) and thus the thrashing is having little/no impact.

In order to find out if this is the case, then just check the speed of the operation, and see if there is a change (or was a change) when the "thrashing started" or if the amount of RAM that is taken up by the VirtualBox process is significantly more than amount of RAM the guest has.

--discard options specifies that vdi image will be shrunk in response to trim command from guest OS. Following requirements must be met:

• disk format must be VDI
• cleared area must be at least 1MB (size)
• [probably] cleared area must be cover one or more 1MB blocks (alignment)

Obviously guest OS must be configured to issue trim command, typically that means guest OS is made to think the disk is an SSD. Ext4 supports -o discard mount flag; OSX probably requires additional settings as by default only Apple-supplied SSD's are issued this command. Windows ought to automatically detect and support SSD's at least in versions 7 and 8, I am not clear if detection happens at install or run time. Linux exFAT driver (courtesy of Samsung) supports discard command. It is not clear if Microsoft implementation of exFAT supports same, even though the file system was designed for flash to begin with.

Alternatively there are ad hoc methods to issue trim, e.g. Linux fstrim command, part of util-linux package.

Earlier solutions required user to zero out unused areas, e.g. using zerofree and compact the disk explicitly (I'm assuming that's only possible when vm is offline).