How Aero Works in Windows7?

Hi,

For Aero to work color depth 32-bit required. But actually desktop's color depth is 24-bit, with remaining 8-bits for transparency. As per my knowledge, 8-bit alpha/transparency exists only in the operating system and they do exist when the desktop image sent out to a physical monitor via VGA/HDMI/DVI connection.

Question here - Does physical monitor showing 24-bit or 32-bit? Incase if it is 24-bit then how transparency part handled?

Please clarify.

Thanks.