Depends on what's in it - i've quad core i7 lenovo laptops that I can get below 2w with 16GB, a 2TB SSD and live Intel gigbit LAN (screen off). 4w is easily believable with one nic (they use 0.5w-0.75w each idle) and a CPU on the latest process.Yeah was surprised by that 4W rating.
I always wonder why the Intel NUCs use over 6w idle when a laptop with the same bits in it (and additional battery circuitry) is a third of that.