Microsoft Virtual PC and virtual video RAM
Tuesday, November 22, 2005
| 1 Comments
|
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 1600x1200 resolutions.
© 2003-2008 virtualization.info
Sitemap
Sitemap


Comments
Actually, as many applications uses double buffering to render smooth animations, there is 2 framebuffers in video memory.
So 8M of VRAM only allow for 2 framebuffers of 1152x864 (1152*864*4*2 = 7962624) and that does not include eventually other surfaces like video overlays.
By
Vincent, at Wednesday, November 23, 2005 9:53:00 AM
Post a new comment