The board is currently advertised with the following CPU speed:
Snapdragon 820E embedded platform, custom 64-bit Kryo quad-core CPU up to 2.35GHz 35GHz , 14nm FinFET process technology
https://www.arrow.com/en/products/dragonboard820c/arrow-development-tools
Based on Qualcomm specs this should be:
CPU Kryo customized 64-bit ARMv8-compliant quad-core processor:
Two high-performance Kryo cores – gold cluster up to 2.15GHz
Two low-power Kryo cores – silver cluster up to 1.593GHz
https://developer.qualcomm.com/download/hardware/sd820e/sd820-product-brief.pdf