Why do intel heatspreaders have a hole in it?

[dEvio]

Why do intel heatspreaders have a hole in it?

 

[PliotronX]

It serves two purposes IIRC; first to create a vacuum under the IHS to insure a tight fit against the core and second to provide relief for the expanding and compressing of the metal in the IHS during temperature fluctuations. Also if you're wondering, it's okay to get Arctic Silver thermal goop in there.

 

[dEvio]

ok thanks