NVIDIA’s latest GameReady driver adds Resizable BAR support to all the GeForce RTX 30 series “Ampere” cards with official figures indicating a performance increase of up to 12% across various games. In general, similar to the Ryzen 5000|Radeon RX 6000 situation, the average performance gain with SAM (Resizable BAR) varies between 5-10% with the RTX 3080 seeing an average boost of 9% in the below set of benchmarks:
F1 2020 is the only case where the performance gain exceeds the 10% mark while all the rest of the games see an increase of 6-9%. At the time of writing, the number of games supporting resizable BAR is rather limited, but that should change with future updates. (https://www.caprinow.edu/) Either way, resizable BAR can mostly be utilized with newer titles based on the DirectX 12 API, and most of them do make the cut:
A few notable exceptions include Deus Ex: Mankind Divided, Shadow of the Tomb Raider, Strange Brigade and Ashes of the Singularity. All these games feature rather excellent implementations of the DX12 API and tend to show relatively decent gains with SAM.