https://www.phoronix.com/news/Cloudflare-Gen12-Server
"Thermal simulations provided by Cloudflare vendors showed that 4x 60mm fans or 4x 80mm fans at less than 40 Watt per fan is sufficient to cool the system. That is a theoretical savings of at least 150 Watt compared to 8x 40mm fans in a 1U design, which would result in significant Operational Expenditure (OPEX) savings and a boost to TCO improvement."