CGM4331 Wi-fi speed

Wifi speeds are not determined by the power of the router (AC1200 or AC5400), but by the physics of the frequencies involved.  The higher the frequency, the better the speed.  5Ghz is good for somewhere between 550mbps and 650mbps, under optimal conditions.  2.4Ghz, while having greater range is limited usually to somewhere in the area of 65-70mbps, although I have seen it go higher. 

Lots of environmental factors go into the speeds that you are going to get.  Metal in the area, other devices that emit EMI (Electro-Mechanical Interference), radio gear, other routers using the same frequency and channel yours is using.  All of that limits the capabilities of your router to deliver good clean signal.  Environmental factors Cox can do little to nothing about, clearing that up is on the user. 

5 ghz has more speed, because it more bands, and they stack the bands. It would do the same with 2.4 if the stacks bands 1--6-11 together. The downside, is so many things use 2.4 ghz, and the distance it travels make it more prudent to use 5ghz due to it's lesser distance. 

5 GHz isn't "faster" than 2.4 GHz because both frequencies travel at the speed-of-light.  5 GHz, however, does have more capacity per second.

5 GHz has twice the cycles per second than 2.4 GHz.  The more cycles per second, the more carrier-waves (wavelengths) per second.  The more wavelengths per second, the more modulation of the wavelengths to represent data.  The more data per second, the more capacity.  Therefore, since 5 GHz has twice the cycles of 2.4 GHz, 5 GHz would have twice the capacity of 2.4 GHz.

The problem with more wavelengths per second is the wavelengths are "shorter" and shorter waves don't penetrate stuff as well as longer wavelengths.  This is why the most powerful radio antennas in the world use extremely-, super-, ultra- and very-low frequencies.  However, because these lower frequencies have "longer" wavelengths, there isn't much modulation per second to carry data.

I'm not sure what you mean by "stack the bands"...nobody does...but channels 1, 6, and 11 are non-overlapping channels, and non-overlapping channels just keep your routers on discreet frequencies to avoid interfering (overlapping) with one another.  However, non-overlapping don't do you any good if you only have 1 router and can't control what channel your neighbor(s) use.

You are partially correct. BTW, Stack the bands is a crude way of saying using multiple bands simultaneously, kinda like the old dual modem shotgun, where you dial up to the telnet carrier with 2 modems at the same time, and stacked them to double your speeds. 

In 5 Ghz, the unmodulated wave has a higher frequency, yes, but that doesn’t inherently allow it to carry more information. The information being transmitted is all carried in the differences between a modulated wave and the unmodulated carrier. In other words, slight frequency, amplitude, and phase variations are what gets interpreted as data, but what frequency is used as the carrier isn’t relevant to its performance, it’s the available width around the chosen carrier frequency that matters. This is a critical point- If I get 20Mhz of space to play with in a channel, it doesn’t matter whether that 20Mhz is centered around something in the 2.4 or 5 GHz range. This is just like radio and TV channels, which live at different frequencies offset from each other to avoid interfering. Channel 5 didn’t get better quality than channel 2 by being centered on a higher frequency.

In 5GHz wifi, there are more channels available, none of them overlap with each other at all, and each channel is allocated twice as much bandwidth than any of the 2.4ghz channels. Because the 5Ghz channels are wider, the newer wifi standards like 802.11ac use more densely packed modulation schemes (more combinations of altered phase/frequency/amplitude are recognized), as well as a trick of using multiple simultaneous streams on multiple channels. This increases the amount of data that can be transmitted simultaneously between devices, and the standard only uses these techniques in the 5Ghz band. In fact, 802.11ac ONLY uses 5Ghz, and gave up completely on operating in the 2.4 band at all. 802.11n (an earlier version) used some of these techniques to a limited degree in the 2.4Ghz band, but the lack of non-overlapping channels and interference from other devices limited its effectiveness and maximum theoretical speed, as compared to doing the same on the 5Ghz channels.

Bottom line, ghz isn't carrying more data because of higher frequency, it's carrying more data because each band doesn't run into the others reducing their capability, and they are wider than the 2.4 ghz bands and the WIDTH of the band is what determines how much data can be packed. 

My point is the WiFi bands aren't "faster" or have "more speed" than one another, but...all things being equal...can carry more data than one another.

I wouldn't suspect radio and TV frequencies could carry more data than one another because they're not double or triple of each other:  2.4, 5, 60 GHz.  What are they...separated by 6 MHz?

Choosing channels and channel widths are just tweaking the bands to improve performance.