ATI has released a new hotfix that should fix the HD 4850 Crossfire X mode issue in Windows Vista. This should fix both the black screen and boot OS failure with two or more ATI Radeon HD 4850 cards in Crossfire X mode under Windows Vista OS.

Until now, users with HD 4850 Crossfire running Windows Vista OS had to stick to 8.11 Catalyst, and according to some reports those that have two HD 4870 are still stuck with the previous driver.

Catalyst 8.12 was something that we eagerly awaited, but it looks like major fixes and performance gains will come with version 9.1.

You can find the new hotfix here.