The counter argument to Renoir is that "harvesting" a tiny, cheaper die is more cost effective than disabling 30% of the shader array from a 500mm2+ chip. That being said, I agree with you. Without knowing the economies of scale, I would expect AMD to cover the gap between 40 and 80CU with defective (or just cut down) big chips, instead of developing a middle sized solution from scrath. with all the costs and market headaches this involves.
The binning process is designed to maximize the usage of dies from a wafer. So whatever SKU strategy AMD adopts for Navi 21 will be done to maximize the total product revenue from a wafer of Navi 21 chips.
Also.
If Navi 21 has 128 ROPs with 256 bit GDDR6 memory bus, wouldn't it be logical if Navi 22 with 40CUs and 192 bit bus to have 96 ROPs, and Navi 23 with 32 CUs and 128 bit bus to have 64 ROPs?
The AMD Radeon RX 5700 XT is based on AMD's all-new Navi 10 GPU featuring the RDNA architecture. We thoroughly test the card's gaming performance and look at power, heat, noise, overclocking, and clock frequency stability, too, sometimes with surprising results.
www.techpowerup.com
RDNA already moved the RBE/ROPs into the Shader Array and each Shader Engine consisted of 2 Shader Arrays. So ROP count scaled with Shader array and not with memory bus width like in previous architecture like Polaris. In RDNA each Shader Array had 4 RBE with 4 ROPs per RBE - 16 ROPs. So the ROP count scaled with Shader Array count. Navi 10 had 2 SE/4SA . So 4 x 4 x 4 = 64 ROPs. RDNA2 made 2 changes.
1.) Halved the number of RBE per Shader Array from 4 to 2
2.) Doubled the number of ROPs per RBE from 4 to 8
So effective ROP throughput per Shader Array stayed the same from RDNA to RDNA2. But RDNA2 scaled to double the Shader engine / Shader Array count of RDNA.
N21 - 4 SE/8 SA = 8 x 2 x 8 = 128 ROPs
N22 - 2 SE/4 SA = 4 x 2 x 8 = 64 ROPs
N23 - 2 SE/4 SA = 4 x 2 X 8 = 64 ROPs
Incidentally Ampere moved the ROP/RBE into the GPC. So they have 2 RBE with 8 ROPs each per GPC. GA102 = 7 x 2 x 8 = 112 ROPs
Looks like we have new data on Navi 2X graphics processors. AMD Navi 21 – 80 CUs, Navi 22 – 40 CUs, Navi 23 – 32 CUs The speciations of the Navi 21 and Navi 22 were already ‘confirmed’ by AMD through ROCm 3.8 software update earlier. The data was pieced together by a Redditor […]
videocardz.com
Look at the Navi 2x table for specs. The front end of the rasterizer (scan converter) has doubled the output compared to Navi 1x .
num_packer_per_sc = 2 for Navi 1x
num_packer_per_sc = 4 for Navi 2x
All RDNA and RDNA2 GPUs have 1 scan converter per Shader Array but RDNA2 has twice the packer per scan converter as RDNA.
num_sc_per_sh = 1