I often find low speeds on home built PCs with owner install Windows. I can't guess why but it seems folk have forgotten or never knew that Windows is just the OS and doesn't always get the best drivers.
The old fashioned ways still work. Install the OS, disable Microsoft's driver updating then install drivers from the makers of motherboard and other parts.
I just done crystaldiskmark and I am confused.
WD Black in my PC have random read and other speeds under 1 MB/s.
Also in userbenchmark I got 3rd percentile with this drive.
Do you know why it can be caused?