The SR650 server supports up to six hot-swap system fans that provide N+1 cooling redundancy: Models with one processor ship with five system fans, and models with two processors ship with six system fans.
Configuration notes: The SR650 FAN Option Kit (4F17A12349) includes one system fan that is required for field upgrades that add a second processor to the server. If two processors are selected in the initial server configurations, the fan for the second processor is derived by the configurator.



LenovoPress - https://lenovopress.com/lp1050-thinksystem-sr650-server-xeon-sp-gen2#cooling