Movie files extremely slow to start on western digital passport firewire drive 1tb

hi there

i just bough this nice looking 1tb MY Studio Passport drive - it has 2 firewire ports and one usb 2.0 for use with my 27" imac running Lion operating system - i moved my movie files over to this drive these are basically 1-4 gb avi and MKV type of files - the only problem is when i try and play the movie files off the harddrive they take a long time to start up sometimes up to 20-30 seconds - when i play the same movie files of the main harddrive or any other external harddrive i have that is usb 2.0 they start almost instant - i even tried to change the cable to usb on this western digital drive no luck - reformatting the drive - NO luck - im very frustrated by this as i bought this drive soley for quick media access - i have never seen a drive this SLOW to play movies - firewire is supposed to be fast !! Any advice would be most appreciated -

try testing the drive on a different computer and see if you have the same issue

test the drive on disk utility to see if any errors

yeah, what is the drive formatted in?  also, I’d not just reformat, but repartition as well.  it could be a bad partition.