First of all thanks for your response Fzabkar.
Unfortunately i’m not in position to compare my drive with another about their weight.
I wonder though how can you assume that my drive has 3 platters and 5 heads (3/5) and not 2/4 as the company describes in here http://rml527.blogspot.gr/2010/10/hdd-platter-database-western-digital-35_3899.html.
It’s for sure something very wrong here but i cannot find it (yet).
I’m gone proceed to a new format and recheck the unpartition drive of 1 TB to see the results.
I’m also gone try a clean windows installation because this one is by cloning and let you inform about the outcome.
Either way do you think is there a reason to RMA the drive?
I payed for more and get less for some reasons.Isn’t that true?
And what about the software controllers?