In addition to Andrew's response, most WiFi monitoring tools such as Acrylic etc, only identify any working WiFi circuits
in your area.
But the 2.4 GHz band is shared with many other, UNLICENSED devices such as microwave cookers, baby alarms, model aircraft controllers etc, for which a Spectrum Analyser is required to detect the whole gamut of devices may be throwing out what appears to be general "Noise" to other systems, with which your lonely WiFi circuit has to compete.
While some of those other systems may only be working for brief periods, such as the microwave cookers, others may be (almost) continuously such as baby alarms.
Whilst you mention the laptop's processor, the WiFi Transmitter/Receiver is a separate unit within the laptop, with different processing powers etc, as is the corresponding WiFi Receiver/Transmitter within the Router.
The laptop's WiFi Tx/Rx is also probably a lot "slower" than the Router's.
So there is a lot of extra processing when using the WiFi connections.
To get a better idea of those extra processing effects, try connecting and using an Ethernet cable connection from the Laptop to the Router, which will then give a much clearer idea of the "Overheads" involved when using WiFi.
This Wikipedia article gives a lot more detail of the general use of the 2.4 GHz Band -
Edited by eckiedoo (Tue 26-Sep-17 11:27:54)