Quoting from Virtual PC Guy blog:
Virtual PC emulates an S3 Trio 64 Video card with 8mb of video ram (VRAM). From time to time I get people asking me why we do not increase the amount of VRAM – and there are a couple of reasons why:
- VRAM is a fixed overhead. Each virtual machine that you launch uses 8mb of your computers memory to store our VRAM information. If we increase this – it will increase the amount of memory used for each virtual machine – whether the virtual machine is using this extra memory or not.
- On video cards with hardware 3D acceleration support VRAM is used for storage of textures, and other performance improving measures. However with a 2D video card VRAM is only used to store a single frame buffer of the contents on screen. This means that with a 2D video card (such as we emulate) adding more VRAM just allows you to support higher resolutions – but it does not provide better performance. At 8mb we are able to display at up to 1600×1200 resolutions.