Monitors with AMD's FreeSync technology are finally shipping, but support for the variable-refresh tech has been limited to PCs with single Radeon GPUs thus far. AMD had promised to release drivers with FreeSync support for CrossFire setups this month, but it appears that there will be a bit of a wait yet. AMD released a message on its support forums today stating that "support for AMD FreeSync monitors on a multi-GPU system is not quite ready for release."
AMD's post doesn't offer any other details or reasoning for the delay. The company says "we will continue to develop and test this solution in accordance with our stringent quality standards, and we will provide another update when it is ready for release." We'll be keeping a lookout for that update when it arrives.