This sets the size of the memory provided by the virtual graphics card available to the guest, in MB. As with the main memory, the specified amount will be allocated from the host's resident memory. Based on the amount of video memory, higher resolutions and color depths may be available.
With this setting VirtualBox can provide more than one virtual monitor to a virtual machine. If a guest operating system (such as Windows) supports multiple attached monitors, VirtualBox can pretend that multiple virtual monitors are present.[13] Up to 8 such virtual monitors are supported.
The output of the multiple monitors will be displayed on the host in multiple VM windows which are running side by side.
However, in fullscreen and seamless mode, they will use the available physical monitors attached to the host. As a result, for fullscreen and seamless modes to work with multiple monitors, you will need at least as many physical monitors as you have virtual monitors configured, or VirtualBox will report an error. You can configure the relationship between guest and host monitors using the view menu by pressing Host key + Home when you are in fullscreen or seamless mode.
Please see Chapter 14, Known limitations also.
If a virtual machine has Guest Additions installed, you can select here whether the guest should support accelerated 3D graphics. Please refer to Section 4.4.1, “Hardware 3D acceleration (OpenGL and Direct3D 8/9)” for details.
If a virtual machine with Microsoft Windows has Guest Additions installed, you can select here whether the guest should support accelerated 2D video graphics. Please refer to Section 4.4.2, “Hardware 2D video acceleration for Windows guests” for details.
Under the "Remote display" tab, if the VirtualBox Remote
Display Extension (VRDE) is installed, you can enable the VRDP server
that is built into VirtualBox. This allows you to connect to the
virtual machine remotely with any standard RDP viewer, such as
mstsc.exe
that comes with Microsoft
Windows or, on Linux systems, the standard open-source
rdesktop
program. These features
are described in detail in Section 7.1, “Remote display (VRDP support)”.