In complex scenes in The Callisto Protocol, my NH-D15S shows huge temperature differences between cores; why?

While sneaking through those creepy hallways, I kept noticing these tiny, annoying hitches that totally ruined the atmosphere. The NH-D15S is a beast, but HWInfo showed a massive 18℃ gap between Core 0 and Core 7. This meant some cores were hitting 95℃ and throttling while others were chilling at 70℃—clearly a mounting pressure issue. I tried messing with thread priorities in Windows, but that's a software fix for a physical problem; it did absolutely nothing. I ended up taking the whole thing off, scrubbing the old paste, and using the cross-tightening method to make sure the base was perfectly flush with the IHS. After the remount, the delta dropped to a tight 5-8℃, and the game felt way smoother. I did have a moment where the PC wouldn't boot because the fan was blocking my RAM sticks; I had to slide the fan up by 2mm to get it to post. CPU temps are now a stable 65-72℃. Benchmarks confirm the pressure is spot on, and RAM temps are sitting at 58-63℃.