Summit or OLCF-4 was a supercomputer developed by IBM for use at Oak Ridge Leadership Computing Facility (OLCF), a facility at the Oak Ridge National Laboratory, United States of America. It held the number 1 position on the TOP500 list from June 2018 to June 2020. As of June 2024, its LINPACK benchmark was clocked at 148.6 petaFLOPS. Summit was decommissioned on November 15, 2024.