AMD fans have been outspoken about their love for the smooth gameplay of AMD FreeSync™ technology, and have understandably been excited about the prospect of using compatible monitors with the incredible performance of an AMD CrossFire™ configuration.
After vigorous QA testing, however, it’s now clear to us that support for AMD FreeSync™ monitors on a multi-GPU system is not quite ready for release.
As it is our ultimate goal to give AMD customers an ideal experience when using our products, we must announce a delay of the AMD Catalyst™ driver that would offer this support. 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
Source
http://forums.amd.com/game/messageview.cfm?catid=454&threadid=186533&enterthread=y