The Gigabyte B550I AORUS Pro AX showed decent headroom for overclocking. I was able to achieve 4.4 GHz at 1.35 V core voltage.
For the B550 launch I am also conducting a memory timing test. This is a pass/fail test where I load the DRAM Calculator "fast" preset for my Trident Z Neo kit (Samsung B-die). A board receives a pass if it can run through three loops of MemTest64 with no errors. Partial credit will be given to a board that can get into Windows, but fails MemTest. This CPU and memory combo with exactly these sticks can run without errors at these settings, as validated by my MSI X570 ACE motherboard.
For high frequency overclocking, the Gigabyte B550I AORUS Pro AX did well enough, reaching 4000 MHz stable at XMP timings and voltages on my Trident Z Neo kit. This is a little shy of what I was able to achieve with my other two B550 samples.
The Gigabyte B550 AORUS Pro was not able to boot into Windows with the tight B-timings.