Drawing is slower in Landscape mode

I found a strange drawing on Windows Mobile. If you draw a Bitmap it takes:
- 3 ms in Portrait mode and
- 65 ms in Landscape mode.
(Tested on VGA emulator)

Method:
e.Graphics.DrawImage(m_Bmp, 0, 0);

It seems the Landscape drawing is emulated only, and the bitmap rotation takes so many time.

It can make problems when you want to animate, or e.g. when you have double buffering and you need repaint some areas on mouse move event.

If you know a faster way of drawing Bitmap, feel free to comment this post.

You can try out my sample here:
http://winmobile.euweb.cz/#Post11

Update:
On QVGA device:
- Portrait: 2 ms (average)
- Landscape: 6 ms (average)
On VGA device:
- Portrait: 6 ms (average)
- Landscape: 47 ms (average)