User`s guide

Troubleshooting and Limitations 200
Increasing the Virtual Machine
Screen Resolution
In virtual machines with Linux guest operating systems installed, dynamic resolution may not
work when increasing the size of the guest OS window or switching to Full Screen mode. It
happens because, by default, only 3 MB of video memory are allocated to such virtual machines'
video cards. If you need the virtual machine screen resolution more than 1024x768, go to the
Video pane (p. 124) of Virtual Machine Configuration and increase the
amount of video memory
available to the virtual machine's video card up to 16 MB.
Memory Usage Problems
The amount of the host computer physical memory required for each virtual machine operation
can be represented as follows:
Virtual Machine Memory = Guest OS Memory + Video Memory + Virtual Machine Monitor
Memory
 Guest OS Memory is the amount of RAM available to your guest OS. You can configure the
guest OS memory amount in the Memory pane (p. 123) of Virtual Machine Configuration.
 Video M
emory is the amount of physical memory available to the virtual machine's video
card. You can adjust the video memory amount in the Video pane (p. 124) of Virtual
Machine Configuration.
 Virtual Machine Monitor is the
module responsible for the guest operating system
virtualization. It consumes memory to peform operations of guest virtual devices and hadle
virtual paging emulation. The amount of memory required for the Virtual Machine Monitor
operation depends on the guest OS and varies from 50 MB to 200 MB.
You can configure the whole amount of physical memory available for all running virtual
machines in the Memory tab of the application Preferences.
Memory Overcommitment
If you have several virtual machines running at a time, and you are trying to start one more
virtual machine, you can come across the memory over commit. The application will inform you
with the corresponding message. This means that all your running virtual machines require more
memory that is configured in the Memory tab of the application Preferences. If you start one
more virtual machine, this may significantly slow down all your virtual machines. To solve this
problem, you can:
 stop one or several of your running virtual machines, or
 edit your virtual machines' configurations to make them consume less memory, or
 edit the application memory preferences to allocate more memory to your virtual machines.