There isn't a jumper on that drive or another that limits it to SATA1 is there? I had something similar on my rig where 1 of my 1.5tb drives was performing much lower then the other. For me it turned out that I had the SATA1 jumper enabled on my 500gb drive which seemed to be affecting it and the next port. Removed this jumper and all has been fine since.
i dont think so?
http://www.myce.com/review/Samsung-Spinpoint-F1-HD103UJ-review-15169/Conclusion-4/
http://downloadcenter.samsung.com/c...419195302781_3.5_Install_Gudie_Eng_200704.pdf