Well...There is only three possible explanations:
1- Seagate makes horible products. [impossible]
2- Both of you got defective hard drives. [unlikely]
3- This SpeedFan program either doesn't work with seagate drives. [the only logical explanation that i can think of]
Best solution is to:
1- try another program that tests hard drives
2- test another seagate hard disk. (if you guys have one)
3- find some other users running seagate disks and ask them to try the program.
If everybody with a seagate has the same problem, then the program doesn't work with seagate hard disks. If you guys are the only ones with the problem, then you may have defective disks.
I just tried the program on my WD 80 Caviar and got 97% fitness and 100% performance. My hard disk is about 4 months old as i use it just about every day.
Hope this info helps.