With Arcturus rumored to lack any graphics hardware-assist, it's looking like it will probably mark a turning point of reserving big fp64 horsepower only for non-graphics chips. That would make Vega 20 probably their last GPU with good fp64. Also, according to https://gpuopen.com/wp-content/uploa...ure_public.pdf

GCN was compute/throughput focused, RDNA is graphics/latency focused
Luckily, for anyone interested in general-purpose GPU compute, Radeon VII is still available from AMD.com, though it's basically sold out, everywhere else.

https://www.amd.com/en/shop/us/Graphics%20Cards

AMD has confirmed that it's being discontinued, leaving would-be buyers only the option of paying inflated prices for the Radeon Pro Vega II version, which will probably cost 2x or more (assuming it's even offered outside of the new Power Mac).

https://www.amd.com/en/graphics/work...on-pro-vega-ii

Also, I think we still (?) don't know the GPU Compute performance of Navi. It does look like scalar performance should be markedly improved, at least. But, for highly-threaded workloads, I don't expect big wins over Vega.