The Summit supercomputer has a staggering 9,216 IBM Power9 CPUs as its compute base. The CPUs are further accelerated by 27,648 NVIDIA Tesla GPUs providing even more computation power. The interconnect is also fast with 25 gigabits per second of interconnect between notes, powered by Mellanox's Infiniband. The system is attached to 250 petabytes of storage.
The operating system running on top of all that power is Red Hat Enterprise Linux.