I don't pay for cooling, data centre provider does. Business' just pay for rack space & power.
My servers run 24/7, as David McAuliffe said customers like me don't really need long term persistence, just a few hours a few times per year during maintenance or extremely rare blackouts. Cooling systems don't cost me anything, data centre provider pays for those. Even companies like AWS & Google just go into the rack's next to mine in Australia, I'm pretty sure they get charged in a similar manner, for power & space, they don't care about cooling much.
If you're referring to the cooling inside the server? RAM only uses about 24-36 watts, nothing compared to CPUs, GPUs & Storage. Not a game changer.
"how about potential bandwidth performance between a volatile and non-volatile memory"
I think thats more important, thats where 4DS can win
