@Viktor it could easily be the enclosure of the hard drive, that fancy thermaltake feature may do something weird that means it takes longer. If possible test with another enclosure or hard drive you have laying around - you could even test with a simple USB stick just to verify if it is the hard drive or not.
As @manne suggests as well try starting over too if you have the patience.
As @manne suggests as well try starting over too if you have the patience.