MSI has confirmed (unofficially) that Re-Sizable BAR or SAM does indeed work with the Zen 2 processors. As per some screenshots shared with WCCFTech, the OEM demonstrated that both the Ryzen 3000 CPUs and the Ryzen 4000 APUs can support the feature via a BIOS update, although, as expected, the performance gains will vary from setup to setup. (Adderall)
Furthermore, these processors were tested with NVIDIA’s RTX 30 series GPUs which means that exclusivity with the Radeon RX 6000 graphics cards is more or less over. We’ve already seen the 1st Gen Zen CPUs support the feature in tandem with the Polaris based RX 580, as well as on Intel’s Z490 and 10th Gen CPUs, in addition to the older B450 and X470 AMD boards.