Navi 10-based AMD Radeon RX 5700 still has elements of GCN, 'pure' RDNA coming only in 2020
AMD kicked off Computex 2019 proceedings by launching Ryzen 3000 CPUs and previewing the upcoming Navi series of GPUs. We've been expecting 7nm Navi to continue using the Graphics Core Next (GCN) architecture as was evident in open source driver code, but AMD announced that Navi will be based on the new RDNA (Radeon DNA) graphics architecture throwing up a conundrum of sorts. However, it looks like upcoming Navi 10 GPUs such as the Radeon RX 5700 will be a hybrid between GCN and RDNA and that the full transition to RDNA will happen only by 2020.
While GCN has catered to both gamers and workstation users, RDNA is developed with an emphasis on gaming. RDNA-based GPUs feature a new compute unit design, multi-level cache hierarchy, and a streamlined graphics pipeline. RDNA GPUs will also be the first to support the new PCIe Gen4 standard for consumers. That doesn't mean AMD has abandoned GCN, though. The current generation (Navi 10) will still carry over elements of the GCN architecture. SweClockers quotes AMD sources who say that offering GPUs with 'pure' RDNA from scratch can have its implications.
GCN is a seven-year old architecture that has been refined through each GPU generation. Game developers have optimized their engines to make the best use of GCN and throwing all that optimization into the bin can prove fatal for Team Red if things happen to go south.
That being said, AMD does feel that the time has come to move on from GCN to RDNA on the lines of the transition from Bulldozer to Zen for CPUs. Unlike Zen, the company is taking it gradually this time implying that we won't be seeing the full benefits of RDNA until 2020 in Navi 20 — which is probably when Team Red will finally have a true competitor to NVIDIA's top-tier offerings.