You hear about Intel meltdown?

[i3oi3o]

Don't forget that XIV performance also relies on server performance. "Server limitations" is a known phrase for us.

I think FF14's server is designed to scale.

Very likely, they choose available server instance which don't have much load and spawn a process to run.
Imaging this process as dungeon instance, each world map etc.

Not likely that a process will consume a lot of CPU except one scenario, 100 people enter the same map to hunt Rank S which very likely causes the process to consume CPU to almost full.