heatsink pressure

[Kaldskryke]

So I had my computer apart and my Big Typhoon simply sitting on top my IHS with paste, but not secured with the screws. I had my BIOS hardware monitor up, and as I applied pressure to the heatsink, temperatures went up significantly.

I had always thought that increasing the pressure would be better for heatsink contact, but this test seems to indicate otherwise. Which leads me to wonder, "just how tight should I tighten these screws, then?"

Any ideas?