no idea where you have read that but i can assure thats not the case and we are talkin g quite minimal differences
tri band router also will always have issues with cross talk between the two 5 gig transmissions
triband wont make your coverage or throughput any faster over the same dual band of the same class
the performance between these will be the same as the asus rt-ac3100 and asus rt-ac5300
you do understand the ad7200 only has 1733M on 5 gig so isnt even in the same class as the other 2156M class routers
The place I "read" this information was from the router ranker section of this site. All numbers compared are from this site only and I also tried to make sure they were the same V9 testing process. See the attached. The C3150 for 5Ghz range, for example, has a higher throughput than the ranges for the other mentioned models.
I am going to stick with the 5Ghz range comparison for most of this for simplicity, but I see that other tests like the 5Ghz Max downlink, 5G avg throughput, and 2.4 G range are a pretty wide margin as well.
I understand that triband will not make wireless performance faster just by having another band, but it will give me the capability to create a mixed mode 5G network for my N devices and another AC only network, which I believe will give me better performance on AC capable devices while still being able to serve my N only capable devices.
As far as the comparison to the AD7200, I was only stating that the physical design of this router is the same as the C5400 VS the physical design of the C3150. Since the C5400 is not reviewed, I am forced to look at something similar. In terms of physical design, I would think to look at the C3200 or AD7200 (Both of which have different 2.4G and 5G theoretical throughputs, as well as amount of antennas.) It is concerning to me that the C3200 is ranked 4th in the router chart, and that some of the stats I am concerned about, like 5ghz range, are very different on the C3200 vs C3150.
This is exactly why I am asking for testing on the C5400, because if the wireless performance is not affected by a physical design change from C3150 and I can get 2 5G bands, I would prefer that. But if by changing the design, or even adding additional bands, degrades performance and the C5400 starts getting results like the AD7200 or C3200 (e.g. C3150 Downlink 5G Range: 259.5Mbps; C3200 Downlink 5G Range: 102.2Mbps) then I think I would stick with a dual band vs triband.