- Jul 18, 2015
The problem is you don't get perfect scaling increase CU's and clocks. We can see this comparing 5700xt and 6900xt, 6900xt is about 2x faster despite 1.18x higher clocks.240 CU's seems extremely unlikely given AMD probably had a good idea of fab capacity constraints coming before Zen3 and RDNA2 were announced last October.
Much more likely is 10-13% clock and 10-13% IPC (FPS per Mhz per CU) boost for each GCD chiplet.
Multiplied by 2 CU's gives a more or less a 2.5x performance increase from the RDNA2 flagship GFX card.
Obviously this is not counting overheads and they may be comparing using a favourable game engine.
I would not at all be surprised to see RT performance gain by more than 25% per CU though - given how early we are in the RT HW saga and how much low hanging fruit likely left to be picked with a base µArch to build on it seems guaranteed that 2.5x would be conservative on that score if they can manage so much with raster gfx.
A 1.13x ipc and 1.13x clock gain would land in the 2.1x area for average performance increase, so to me 240CU's make more sense.
You need brand to make money but I still don't see what mi200 has to do with RDNA3. AMD is selling gaming cards right now despite having higher margins on mi100.A 240 CU RDNA3 GPU would be significantly larger than a 240 CU CDNA GPU, and there's no chance AMD would sell a larger die for a lower price to gamers vs selling the insane high profit margins datacenter GPUs.
So far I haven't seen Navi32 anywhere so I don't know what it is.
I get 800-1000mm2 for a 240CU monolith die using 0.6-0.7x scaling for 5nm, 1 chiplet should be around 300mm2.