I have similar problems, the amount of uncoordinated disk accesses that seem to happen constantly are murder for older spinning disks. After a while it levels out but that's usually after the first hour of usage- resource monitor clearly indicates what sent my disk queues up as Microsoft code that's recommended to be on such as defender. An SSD is absolutely required, or at least a modern hard drive with SATA 3.0 instead of SATA 2.0 for the extra iops.