So, in one hand, quad channel RAM (increased bandwidth) doesn't matter because of past experience (pre-Skylake). Completely disregarding the fact the Skylake was the first Intel CPU to memory bandwidth starved, and saw large gains in performance with greater memory bandwidth. On the other hand, you state Ryzen requires the as much memory bandwidth as possible because it is different from past AMD CPUs.
So have you seen information/test results regarding how Skylake-X (X299) handles quad channel memory that the rest of us have not? I generally do not like to assume, but I think it is a safe bet that the test results will differ from Haswell/Broadwell simply from the fact that Skylake was much different.
After reading all your posts, it is clear that you are an AMD fanboy and will do your best to continuously move the goalposts to fit your agenda.
You are twisting his statements.
In the second quote he states that with dual channel more BW is good when you got 8 cores while the second part on his statement is about latency not bandwidth. AMD's interconnect is linked to memory clocks so latency decreases as you clock the DRAM higher and this is why DRAM oC is more rewarding than on Intel. It's not just inter-CCX that has lower latency though, memory latency scales better too.
Maybe also notable that AMD has higher latency but higher bandwidth than Intel and it's safe to assume that remains true with Skylake X. AMD hits very close to theoretical bandwidth so you can't really do better.
The number of memory channels is not about just bandwidth. Cost ( both die size and system costs) and power are highly important and then there is the actual need for more channels.
AMD with 8 cores and 4GHz is fine with the DRAM at 3200 ,especially in consumer.Intel with higher IPC, not that much higher though when you factor in SMT, it's not really limited in consumer with 8 cores bellow 4GHz either. With more cores and/or higher clocks they would start to be limited in some scenarios with current DDR4 speeds-prices are high and above 3200 they really get too high.
Intel with quad channel for 12-18 cores is really starving them though, we'll see how high they clock them as the TDP will be limiting but there is no way out really.
I'll assume you understand what the theoretical limit is for bandwidth and that it's a hard limit , you can't do better than that at a given memory speed.
Maybe if DDR4 4400 becomes more affordable (slim chance as DRAM are still rising but might stabilize towards the end of the year), it gets better but we'll have to see how Skylake X scales with memory or if scaling stops well bellow those speeds.