Gopro footage and import in FCPX

Hello,

I´m totally new to fcpx and yesterday I tried for the first time to import gopro footage taken from a dive trip. The footage was around 50 GB of data and I imported it to fcpx, but my real question is- the conversion time was around 6 hours on my mpb early 2011, 8 gig ram. Is this normal?
The data that was converted was saved on a g-raid 4 tb hdd connected with firewire 800.

Another question I have is that the converted data was around 500 GB:(!!! Thats insane right? The converted footage was also not in 1080p but in 720p.

How do you guys convert gopro footage to fcpx? Because I seriously think im doing something wrong here.....

Thanks in advance....