RX 7900 GRE - question about performance - OC vs undervolting

Help me understand this: I just ran two benchmarks in Cyberpunk 2077. One where I completely maxed out what my card can do: 2803mhz on the core and 2620mhz on the memory. Voltage at 1000mV and power limit at 115%. I scored 105 fps with these settings. Then I tried reducing settings to 2500mhz on the core and only 2360 on the memory, and voltage at 960mV. Now it scores 106 fps. Temps did not exceed 52C during these tests, so it's obviously not a temperature issue. What gives?