Well from what i see, your coins are new, you received 8 bitcoins and sent them in a hour without fees so priority is low.
There are only 22 confirmations of that transaction.
Ps: If you read wiki
A transaction will be sent without fees if these conditions are met:
It is smaller than 10 thousand bytes.
All outputs are 0.01 BTC or larger.
Its priority is large enough (see the Technical Info section below)
https://en.bitcoin.it/wiki/Transaction_fees