You may also find the performance to be severly lacking if by "intense graphics" you are talking 2D or 3D rendering as virtualization is not designed for applications with those type of video requirements (just like citrix is not designed to run application like that very effectively).
If you are just refering to a large color scale (ie, 32bit depth of color range) then I would suggest using the advise already given to increase the video memory for the VM plus you will almost cirtainly need to do the following GP Policy setting. In my testing without adding the additional memory setting the best I could get RDP to connect using was 24bit color (not 32bit color), but only after enforcing that policy below. Every other client side setting gave me 16bit color.
Set Group Policy for Maximum Color Depth of Terminal Services
In many cases, after you perform these steps, the client still connects with 256 colors rather than whatever value you specified in the Remote Desktop Connection box. This behavior can occur because of a group policy on the Windows XP-based computer that determines the maximum color depth that can be negotiated by the client. In Windows XP, the default policy setting is 256 colors, but this setting can be changed by using the Group Policy Editor.
To use the Group Policy Editor to change the setting, follow these steps:
Click Start, click Run, and then type MMC.
Click the Console menu, click Add/Remove Snap-in, and then click Add. Select Group Policy.
Click Add, make certain that Local Computer is selected in the Group Policy Object box, click Finish, and then click Close.
Select Computer Configuration, click Administrative Templates, and then click Terminal Services.
Select Limit Maximum Color Depth and set it to the color depth that you want.
After you change the setting, you should be able to specify any setting of more than the default 256 colors setting and have the client connect with that resolution, as long as it is not higher than the setting that you specified.
NOTE: You cannot specify and connect at a higher resolution than your video hardware can support. Therefore, if you have a video card in your computer that supports only up to 256 colors, you cannot connect to a session with a higher resolution than that.
