So for that it's "Easier" because you check the VRM spec for the socket for server. That's the maximum draw the manufacturer expects any CPU for that socket to ever pull. Then generally most of the higher end parts will vary clock speed vs cores etc to stay on that line.
This works because server motherboard manufacturers only ever build to that spec and not one iota beyond it for cost reasons.
But yeah... average expected draw is going to be interesting and most manufacturers won't give a number to avoid getting sued.
Yeah, but the mobo manufacturer has to plan on you putting in the thirstiest chips on there, when you might be putting lower end chips on because your workload is mostly memory or PCI channel constrained and you are looking to max out the density in the rack.
Of course you also have to consider the cooling capacity of your chassis. 170W in a 1U form factor needs a hell of a lot of airflow to avoid thermal throttling, especially on a dual CPU motherboard. Plus you gotta fit the power supply and everything else in there.
This works because server motherboard manufacturers only ever build to that spec and not one iota beyond it for cost reasons.
But yeah... average expected draw is going to be interesting and most manufacturers won't give a number to avoid getting sued.