New Firmware for ATI X1900 XT

Apple released an update dedicated to the ATI Radeon X1900 XT card featuring 512MB VRAM.
As usual Apple does not provide information regarding improvement to be expected with this new ROM. Is it linked to Leopard?
To download the firmware update: http://www.apple.com/support/downloads/atiradeonx1900xtfirmwareupdate.html