Lucamarkio:
I'm dealing with 100cm pieces of these strips http://www.entityel.com/datasheets/1300ENSTRIP5-120.pdf ( 60 of them)
If a full 5M strip draws <=48W@12V that's <=4A. Each of the 200 3-LED segments (2.5cm) draws 20 mA. Your 100 cm (1 M) segments should draw 800 mA (9.6W @ 12V).
What made you think your strips were 5W?