According to WCCFTech, AMD commented on Facebook that they are “putting the finishing touches on the 300 series to make sure they live up to expectation”. I tried look through AMD's “Posts to Page” for February 3rd and I did not see it listed, so a grain of salt is necessary (either with WCCF or with my lack of Facebook skills).
Image Credit: WCCFTech
The current rumors claim that Fiji XT will have 4096 graphics cores that are fed by a high-bandwidth, stacked memory architecture, which is supposedly rated at 640 GB/s (versus 224 GB/s of the GeForce GTX 980). When you're dealing with data sets at the scale that GPUs are, bandwidth is a precious resource. That said, they also have cache and other methods to reduce this dependency, but let's just say that, if you offer a graphics vendor a free, order-of-magnitude speed-up in memory bandwidth — you will have friend, and possibly one for life. Need a couch moved? No problem!
The R9 Series is expected to be launched next quarter, which could be as early as about a month.