SS-1 supercomputer cooling system

To achieve the speeds required of the SS-1 supercomputer, a high power ECL chip set was developed for the CPU. The 0.65 cm² chip has an absolute maximum power of 40 watts, translating to a chip level heat flux of 95 W/cm². To achieve minimum signal line length, a compact 3D packaging configuration is required. Board pitch in a 3D module is 2.1 cm for the double-sided CPU and 1.96 cm for the double-sided memory. The corresponding board level heat flux is 15.4 W/cm² and the 3D power density is 3.24 W/cm³. The SS-1 mainframe dissipates 61 KW with an additional 11.5 KW dissipated in the I/O concentrator. Heat must be removed at a high enough rate to maintain chip temperatures at 65°C average and 82°C maximum to ensure reliability and functionality. This paper describes how SSI meet this challenge by a novel liquid impingement cooling methodology