I'm attempting to use VirtualBox to play a game on a Windows guest machine, running under an OSX Mavericks host with 512MB of video RAM. The game requires 512MB of video RAM (although it doesn't do anything particularly intensive, graphics-wise).
The slider in the configuration screen only goes up to 256MB.
I tried
VBoxManage modifyvm "Name of VM" --vram 512
but that did not work:
VBoxManage: error: Invalid VRAM size: 512 MB (must be in range [1, 256] MB)
VBoxManage: error: Details: code NS_ERROR_INVALID_ARG (0x80070057), component SessionMachine, interface IMachine, callee nsISupports
VBoxManage: error: Context: "COMSETTER(VRAMSize)(ValueUnion.u32)" at line 570 of file VBoxManageModifyVM.cpp
As I understand it, video RAM is emulated using regular host RAM, so I don't see any reason for such a limit. Is there a way to increase guest video RAM past 256MB?