The array shoudd be much faster, especially with just one data drive which makes work similar to a RAID1 array, two things you can test, copying directly to a disk share instead of user share, you can enable disk shares on settings -> global share settings, then copy to \\tower\disk1, another thing would be to add an SSD as cache, for either test do a standard SMB copy using Windows explorer, from a Windows 10 PC if possible.