The latest on AMD's upcoming Radeon RX Vega is that there are indeed 4 different versions, 3 with 8GB of HBM2 and a higher-end model with 16GB of HBM2.
VideoCardz is reporting that the latest Vega GPU engineering samples have varying clock speeds, starting with the first RX Vega with 8GB of HBM2 having a GPU clock of 1000MHz, an unknown HBM2 clocks. The second model has its Vega CPU clocked at 1.2GHz and its 8GB of HBM2 @ 700MHz, while the highest end 8GB model has its Vega GPU @ 1.5GHz and its 8GB of HBM2 at 925MHz. I think this one will be the GeForce GTX 1080 Ti competitor, while the 8GB @ 700MHz model will be the GTX 1080 11Gbps competitor, while the 8GB @ unknown will be the GTX 1070/1080 competitor.
But it's the 6861:00 card and its 16GB of HBM2 that has me intrigued, with the mysterious piece of technology having its Vega GPU @ 1GHz, while its 16GB of HBM2 are clocked at 700MHz. If I'm right and the 8GB HBM2 @ 700MHz model is the GTX 1080/1080 11Gbps competitor, a dual-GPU with 16GB of HBM2 and both of those cards clocked at 1.2GHz on the GPU and 700MHz on each 8GB cluster of HBM2, we could be in for a very wild ride.