Each one of its 4,608 nodes (9,216 IBM POWER9 CPUs and 27,648 Nvidia Tesla GPUs[12]) has over 600 GB of coherent memory (6×16 = 96 GB HBM2 plus 2×8×32 = 512 GB DDR4 SDRAM) which is addressable by all CPUs and GPUs plus 800 GB of non-volatile RAM that can be used as a burst buffer or as extended memory.[13] The POWER9 CPUs and Volta GPUs are connected using Nvidia's high speed NVLink.