After two hours of Metaphor: ReFantazio, my AK620 seems to heat soak. Should I optimize fans?

I was walking through town and noticed my frames slowly dipping from a solid 120 down to 85. Classic heat soak. The AK620's dual-tower design is great, but in low-pressure cases, heat just traps in the middle fins, leaving the CPU hovering between 82-88℃. I tried 'High Performance' mode in Windows, but that just pushed the CPU harder and hit 92℃, triggering a slight throttle. Total fail. I bumped my front intake fans to 1500 RPM and set the AK620 curve to hit 100% at 70℃. RTSS showed my 1% lows climbing back from 40 to 62-68 FPS. I did notice a weird humming noise from the fans being out of phase, but that went away once I synced them to the same PWM signal. Now temps are steady at 68-75℃ and frame times are locked at 5.1-6.4ms. It took way too much tinkering, but it's finally sorted.