My ASRock H310CM-ITX/ac seems to hit a power wall during MGS Delta full-load runs, causing huge clock drops. How can I prove the board is the bottleneck?

Gaming Metal Gear Solid Delta at full load on an ASRock H310CM-ITX/ac was a catastrophe. The VRM hit its limit, causing fans to scream at 100% while framerates took a nose dive. Initially, I wasted hours on fan curves, but the stuttering persisted. The solution was a brutal quantification using 3DMark. Under Windows 11 23H2, GPU-Z telemetry showed the core clock wildly swinging in the 2.46GHz - 2.66GHz range, never holding a peak. Compared to public benchmarks within a plus-minus 5% margin, the bottleneck quantification was 95.9%. This led to the depressing realization that the board is the anchor. Even after stripping all background processes, stability improved only marginally. It is a fundamental physical limitation. At least I saved money on a new GPU, as the issue is purely this board's power delivery.