faulty hdd?

hi, 5 days ago i bought new 2.5" hdd samsung hm640jj (640gb, 7200rpm, 16mb cache) and put it into hp 6710b.
i have done some hd tune pro benchmarks and here are results:


short stroke - 60gb:


short stroke - 120gb:


dos hdd test (forgot name):


all tests show transfer speed loss at same places. first appears between 30-40gb. then there are 3 between 70-115gb, and so on.
some pic are from system in sata native mode, some in ahci mode - no difference between this 2 modes.
seems there are no bad sectors.
does not matter if benchmarks were done in fresh win xp sp3 install or in dos or in mini windows xp (hirens 10.5).
s.m.a.r.t. shows warning: 0b calibration retry count 100 100 0 1

i will take hdd back to seller but don't want to look like an idiot in case of my fault. would like to know your opinion if it is hdd fault or maybe notebook can't work with hdd properly - there is hp's "advise" not to use 7200rpm hdd larger than 120gb but it was in 2006 and i think it is about ability to dissipate heat. old hdd hitachi 160gb 5400rpm had higher temperatures. i haven't opportunity to try hdd somewhere else.
thanks for help
marian

 

Test with a known working hard drive to rule out the motherboard SATA controller.

 

previous hdd (but with backround applications like avira...):

as soon as i switch hdds i can retest hitachi again