SiSoft benchmark detected 64 Compute Units on 687F:C3 device (so not C1 like in the previous leak). This device has 8GB 2048-bit memory configuration, which means two HBM2 stacks, each 4GB and 1024-bit. When it comes to core clock (344 MHz) and L2 cache (16 kB), those are definitely wrong readings, so I wouldn’t pay attention to them.The conclusion here is that Vega engineering samples are getting tested but it's not possible to draw any conclusions about how this card will stack up versus the NVIDIA GeForce lineup.
Source: VideoCardz