It's hard to say from that recording, but if it is the clicking sounds I think I hear, then it is just the head seeking different cylinders. Data can be on different locations so far as where the head must be between outer radius and innermost radius. If a single file has tracks only on directly connected cylinders, then the head has very little seeking it must do and doesn't produce much noise in comparison to when the data is spread out across multiple cylinders. Having everything contiguous implies the disk is not "fragmented", having data spread around is not a bug, but is considered "fragmented". Performance suffers when data cannot be read continuously and must reposition the head for read/write. Defragmenting the drive is a software operation where Windows will attempt to take files spread out across the disk and consolidate them so the head doesn't have to seek as often nor as far. Both noise and performance would improve if the disk can be defragmented. Check out defragmenting for this disk. Some clicking is normal, clicking where the head assembly collides with something is not. Your recording can't differentiate.