Die size? If you're targeting 1080p, you likely don't need more than 10CU of RDNA2 for playable frame rates. Clocked up over the 6xxx parts by 10% should give the needed Tflops for it. The trick is having the full frame buffer in cache and also enough for the RT scratch space. No matter what, it's going to be RAM bandwidth limited without it.
Ray Tracing isn't happening on "free" iGPUs for 4-5 years at least. There just isn't enough performance for it. You have tons of better things to up the quality before you need RT, such as setting all options high, and minimum of 1080p resolution, or having everything playable at 60 fps or more.
Maybe if integrated means something like Kaby-G, where it uses tons of power and was just as expensive as dGPU parts sure.
On iGPUs, they can simply up the cache size of the CPU LLC and just share it like they do on Intel chips. Sharing the 8MB cache on Sandy Bridge resulted in 10-15% improvement. Tigerlake has 12MB L3 it shares between the CPU and the GPU.
AMD talked about roughly 1/3rds of the 54% perf/watt improvement coming from the L3 cache. That's actually not too far from the LLC sharing gains Sandy Bridge got.
N5P should be a step forward but it seems that N5 is not as great as it was expected.
Not surprised. It's slightly more than a half node by historical definitions. I'd call it 0.6 node.
Density gain sounds great but perf/watt is the main issue.