Both upcoming cards have a single-slot cooler, 800 Stream Processors, a GPU frequency of 850 MHz, a 128-bit memory interface, 1GB of GDDR5 memory @ 4800 MHz, DirectX 11 and CrossFireX support, and one 6-pin PCIe power connector.
XFX's HD-577X-ZMF3 and HD-577X-Z5F3 are expected to be released around mid-August and will cost about $200 and $207, respectively.
Source: TC Mag