They're threaded lugs. The heatsinks had holes, and nuts were used to secure them to the processor. https://commons.wikimedia.org/wiki/File:Inside_a_DEC_AlphaS

They're threaded lugs. The heatsinks had holes, and nuts were used to secure them to the processor. https://commons.wikimedia.org/wiki/File:Inside_a_DEC_AlphaServer_1000A_5-400.jpg https://commons.wikimedia.org/wiki/File:Inside_a_DEC_AlphaSe...