MarRumours, why the heck can't you leave posts about Bootcamp issues alone at the iMac forum? This is a like a slap in the face to us Bootcamp users. Apple.com doesn't have a working support page for iMac Pro Bootcamp, and the drivers at this stage have several big issues (audio, graphics, peripherals). And you insist on dumping these issues in this little used forum. This is just ridiculous.
PS: There is no auto brightness, because these unofficial drivers is a stop-gap solution until Apple chooses to properly support iMac Pro Bootcamp, and are basically Radeon 580 drivers. Just be happy that you can actually game with these drivers, and getting decent performance.