Ramon

I found your post because I was having the same issue, oddly I first noticed it on only one of the drives when I was pre-clearing them. the write speed dropped to about 40 MB/s, it only happened when writing zeros on one drive, all other stayed at about 180 MB/s when writing zeros. however, after adding the drives to an array, I confirmed that they would all start writing at the expected gigabit network speed of about 110 MB/s, but then drop to 45 MB/s with a few minutes. the solution was setting the write cache to enabled as described here: https://forums.unraid.net/topic/72862-drive-write-speeds-really-slow-solved/?do=findComment&comment=670028