I have some thoughts and did bit of google search recently, but could not find the answer.
Has anyone thought about this:
Why NGFF M.2 ports can be connected with pci riser for mining (as the picture below), while SATA ports cannot?
SATA only supports up to 6Gbps atm which is a lot lower than PCI-E/M.2 theoretical speed. However, my understanding is that the data transfer speed is not very high between the GPUs and mobo when mining, the heavy workload is really on GPU, not on transferring "data" when mining, it is not like you copy hundreds of gigabytes of data from one place to another.
For example, mining only requires a relatively stable internet connection, when you need to send and grab data from the pools but you dont really need it to be lightening speed fast - I have the lowest speed fibre connection and I am always streaming, bit downloading and mining at the same time, never had a problem, even if the full bandwith of internet connect is reserved for mining, it will be way less than SATA speed, isnt it? I know they cannot be compared this way, but this is just an idea.
Unless - what I could think of is that it is a Southbridge/Northbridge issue. Having said that, I think people say some M.2 are part of southbridge?
Can anyone give some answers please?
The reason for this consideration is that if SATA ports can be utilised for mining, a lot of old mobos can be used again, epseically those Hx1 series (H61/H81) boards, which do not have many PCI-E ports, and we all know eth mining does not require a high speed cpu/chipset.