When
J65nko mentioned 4096-byte alignment in post #4 above, I had an epiphany -- in regards to another thread on drive performance.
This post of mine describes the steps a drive takes to conduct an RMW operation. Alignment is one way to minimize extra RMWs.
Keep in mind: data transfers of a sector occur in
microseconds. Seeks and rotational latency (RPS Miss) occur in
milliseconds. They take
three orders of magnitude longer to execute. Anything you can do to eliminate seek or rotational delay should be done.
Your WD Red and Green drives are "Advanced Format 512e" devices -- internally they are 4096-byte sector drives, for capacity, which present 512-byte sectors to an OS for compatibility reasons. RMWs will occur when conducting write operations.