带宽与发热相关

https://www.quora.com/What-effect-does-Memory-Bandwidth-have-on-Smartphones

Actually it's not CPU's memory bandwidth but the bandwidth of the RAM that the SoC (System On a Chip) has.
Snapdragon 615, 820 etc are not CPUs but SoCs which consists of components like CPU,RAM,storage etc.
The higher the memory/RAM bandwidth is the faster will be the swapping of data between CPU's cache and RAM.
So, in a nutshell the CPU will be able to access the data faster from RAM with higher memory bandwidth. (assuming that CPU can also support that much bandwidth)
There is another thing like the bandwidth of storage on SoC. Faster storage will result in faster loading i.e copying of data from storage to RAM, which result in faster opening of apps.
Coming to the point that why people don't talk about it…I think it is because they only consider the things which are ADVERTISED to them by the manufacturers instead of learning about the whole SoC.

关于手机发热问题
https://answer.uwa4d.com/question/613acebc8f8c8342419e98ce