Seagate Freeagent HD - installation went funny

Hello all, Im not very good with computers so I need some explanation please..

My macbook's hard drive broke so I bought a Seagate freeagent HD to use it as a booter until I got chance to have my mac repaired.
I did manage to install OS on it without any problems except it took 7 hours... I was aware that it might be a little bit slower but I wasnt expecting that...)

Can someone please explain me why did it take so long? It's an usb drive and the speed is the same as the mac (5400prm)... If it does count at all...

Thanks in advance!

How old is that macbook you have?

Its about 2 months old.....

maybe the installation had to format the drive to HFS before the installation could start

even so, I would expect it to be quicker than that, the cable the one that came out of the box with the drive?

louishen - thanks for your reply

before the installation started, the drive was already formatted for OS -which was done in no time...

as for the cable - I used the one which came with the drive... Ive read some recommendations so I was sure about this drive... Anyway, it seems to be working fine since then...