I bought my 17inch macbook pro in may 2011. I replaced hard drive to Crucial M4, Didnt compatible. Then changed to Intel 510 250Gbs. It much better then M4. However, I still have problem with unstable and one of more serious problem. The sata 3 negotiated link speed usually is 6Gbs. My ssd only run 3 Gbs. And really slower than nomal.This is image shows evidence.Is anyone can give me the answer? Thank you!