ASUS has reportedly released a BIOS for one of its B450 boards that supports SAM or Re-Sizable BAR on the 1st Gen Ryzen CPUs. Someone over at Reddit was able to test this out with a few games and the results are rather interesting.

Although this means that SAM works with the older Ryzen CPUs, the potential performance gains are within the margin of error, explaining why AMD isn’t willing to spend resources to officially support it.

The CPU tested was a Ryzen 7 1700 paired with an ASUS B450-PLUS motherboard using the 2409 BIOS version. The system ran a Radeon RX 580 which is a pre-RDNA Polaris part, so it’s possible that gains with older graphics architectures are minimal.
Regardless, even with the latest hardware, as we discovered, SAM provides minor gains, and that too even in select titles.