How do I stop my Noctua NH-D15 G2 from heat soaking and causing micro-stutters after a few rounds of R6?

By the third match, I started noticing this subtle screen tearing and a lack of fluidity that is absolutely lethal in a tactical shooter. The Noctua NH-D15 G2 is a beast, but my case's top exhaust was restricted, creating these tiny heat vortices between the fins. My CPU temps started creeping up from 65℃ to a nasty 84-89℃. I tried just cranking the fans to max, but the noise was insane and temps only dropped 2℃—totally useless. I ended up rearranging my front intake fans and flipped the top fans to a high-pressure exhaust mode, while also shifting my RAM heatsinks to clear some space. Checking the sensors, temps plummeted back to 68-73℃. I actually messed up and accidentally triggered the motherboard's 'Silent Mode' during the process, which tanked my fans to 400 RPM until I manually switched back to Standard. Now the CPU holds at 4.8GHz without any thermal throttling. After a three-hour marathon, the stutters are gone and VRAM stays between 58-63℃.