   Copying from one backbuffer to another...
  I'm trying to copy from one backbuffer surface to another using the following code:[source lang=c#]  public void GlowMesh(SurfaceMesh mesh, Color color)   {  this.device.EndScene();  //store original buffers and data  Surface backBuffer = this.device.GetBackBuffer(0, 0, BackBufferType.Mono);  int width = backBuffer.Description.Width;  int height = backBuffer.Description.Height;  Format bbformat = backBuffer.Description.Format;  Material omat = this.device.Material;  Color clearColor = Color.Black;  //set render parameters  this.device.RenderState.Lighting = false;//disable lighting  Material mat = new Material();  mat.Ambient = color;  mat.Diffuse = color;  mat.Emissive = color;  mat.Specular = color;  this.device.Material = mat;  //render to targets  this.device.BeginScene();  this.device.Clear(ClearFlags.Target | ClearFlags.ZBuffer, System.Drawing.Color.Black, 1, 0);  mesh.mesh.DrawSubset(0);  this.device.EndScene();  //copy newly rendered mesh  Surface target = this.device.GetBackBuffer(0,0, BackBufferType.Mono);  //copy data to original buffers  Rectangle rec = new Rectangle(0, 0, target.Description.Width, target.Description.Height);  this.device.StretchRectangle(target, rec , backBuffer, rec, TextureFilter.None);  //SurfaceLoader.FromSurface(backBuffer, target, Filter.None, clearColor.ToArgb());  // place composition into render target and release memory and restore state  this.device.SetRenderTarget(0, backBuffer);  target.Dispose();  backBuffer.Dispose();  this.device.Material = omat;  this.device.BeginScene();   }when I try the copy it get's really slow and I can't really work with it.  Am I doing something wrong?  I'm just trying to render to a blank area after storing the rendertarget and then copy from the first to the second.  Then set the composition to the rendertarget.Thanks in advance,Devin   
  Physically copying the data is going to give you terrible performance, since transfering those huge surfaces to and from the graphics card is extrememly slow (not to mention the time it takes to actually copy).  Instead, just try rendering the current RT to the backbuffer as a textured quad.  You can use ID3DXSprite for this, if you want.   