There are more rumours coming out about RDNA2 floating around. There's a video on youtube but the guys a dick and has bad teeth, so here's a summary.
*60% performance per watt uplift
*No HBM2
*Not using 512bit bus. Lower Bus width
*Infinity Cache on the GPU 128MB which helps make up for the lack of memory bandwidth of GDDR6
*Clock Frequency similar/around PS5
*80CU for top sku
*6700, 6800, 6900 skus
*6700 will compete 3070
*6800 will compete against the 3080
*6800XT will compete against the 3080 TI
*6900 will compete 3090 but will be faster than a 3080TI. Not sure if it will beat a 3090
*No word if they will undercut Nvidia pricing.
*Hybrid Ray Tracing (AMD Patent)
*Up-sampling handled via lower precision operations.
*Decompression: unknown at this time
*This will not be another Vega64