Scrolling too heavy on huge HTML even the HTML is simple

I made a test HTML from [http://www.gutenberg.org/files/1661/1661-h/1661-h.htm](http://www.gutenberg.org/files/1661/1661-h/1661-h.htm) using SGMLReader as I suggested on issue 90.

When I clicked down button on the vertical scroll bar , scrolling took couple seconds.
After I displayed the bottom of the HTML , I clicked up button , scrolling didn't take so much time.

Now I'm avoiding this trouble;
`htmlrenderer\core\htmlcontainerint.cs

///
/// Render the html using the given device.
///
/// the device to use to render
public void PerformPaint(RGraphics g)
{
ArgChecker.AssertArgNotNull(g, "g");

bool pushed = false;
if ( MaxSize.Height > 0 )
{
g.PushClip( new RRect( _location.X , _location.Y , Math.Min( _maxSize.Width , PageSize.Width ) , Math.Min( _maxSize.Height , PageSize.Height ) ) );
pushed = true;
}
else
{
//g.PushClip( new RRect( MarginLeft , MarginTop , PageSize.Width , PageSize.Height ) );
//pushed = true;
}

if ( _root != null)
{
_root.Paint(g);
}

if ( pushed )
{
g.PopClip();
}
}
`