SataIII SSD and 1,5 negotiated speed MBP5,1
The problem stems from what i believe with that model is that if you stuck the hard drive into the optical drive bay the actual link speed of the SATA in that bay is only SATA I (1.5 Gigabit). If you take that hard drive out and swap places with the hard drive in the regular slot you should be able to get full SATA II out of your SSD and should not notice much of a speed difference of your old hard drive if it is placed in the SATA I optical drive slot.