The highest value that is above 100% for any input rail, in "%" value, including rails not visible in hwinfo. Most of these rails can be seen in the old Ampere Bios Editor. A few, like NVVDD voltage (amps), MSVDD amps and PLL cannot be seen but still report to normalized. The NVVDD and MSVDD voltage rail powers that you can't see are heavily affected by shader usage, and will usually not reach 100% (and cause a throttle flag) except on cards with a >480W TDP or shunt modded cards.
For 400W or lower cards, the biggest culprit for a high TDP Normalized are too low 'Memory' power rail limits or PCIE Slot power rail limits (which can sometimes be worked around by crossflashing another AIB bios, or completely removed by using the Galax 1kw bios for 3080 Ti cards only, or the Kingpin 1kw bios for 3090 cards only).
A TDP slider that goes past 100% will affect TDP Normalized's limits as well. Normalized is not affected by the TDP slider set below 100%, e.g. only the 100% normalized values will throttle you by overriding TDP% itself if you limit yourself to a lower TDP.