Preface: THIS THREAD IS FOR THOSE INTERESTED IN TECH ANALYSIS/DISCUSSION OF RDNA 2 AND THE DESIGN CHOICES FOR PS5 AND SERIES X. NO CONSOLE WARS PLEASE!
https://www.computerbase.de/2021-03/amd-radeon-rdna2-rdna-gcn-ipc-cu-vergleich/2/
Awesome analysis that I think is the most comprehensive in comparing RDNA 2 CU scalability between AMD 6000 series cards, all fixed at 2ghz clock frequencies. Results posted below, but I wanted to point out a crucial point from a different but related test they conducted that determined RDNA 1 CUs are actually faster than RDNA 2 CU due to the shorter ALU pipeline (this should serve as a reminder to some that RDNA 2 isn't inherently better than RDNA 1 across the board AMD) .
Applying the findings below to the premium consoles, there are a few interesting facts from my perspective:
1. Cerny's argument of CU utilization doesn't pan out in the games tested below. CU scalability remains relatively constant from 1080p-4k. Although it is possible that current gen games could yield a different outcome.
2. Series consoles chose RDNA 2 design with inherent CU latency increase compared to RDNA 1, without offsetting via higher clock frequency (2ghz+) as AMD and Sony have done with 6000 series and PS5, respectively. Based on the testing, it doesn't appear as though Series X 560gb/s throughput would be enough to compensate to achieve the levels AMD was able to with faster clocks/cache. As shown below, A 50% CU advantage AND 33% bandwidth advantage for the 6800 over the 6700xt resulted in only 36% performance increase at 4k (
again, both GPU clock frequencies fixed at 2ghz). Series X has 44% CU advantage and 25% bandwidth advantage ceiling over PS5 with its fastest memory segment.
If anyone has information as to why Microsoft deviated from AMD RDNA 2 strategy, I would be interested to learn about this (proprietery hw/sw, etc.).