You are using a 1st Generation SATA-150 controller. X25-M will only reach higher transfer rates, if you plug it to a SATA-300 Controller (2nd generation). On such a controller, transfer rates will reach like 250MB/sec maximum for a single port. So it's a hardware limitation of your platform. Since you are using a notebook there's not much you can do unfortunately. What you won't lose though is the high random write/read performance of the drive, so it may still perform pretty well on your 1st gen SATA controller. Just for sequential reads you'll not get the optimum on that notebook.
Its nothing wrong.
Your chipset, ICH-7M (82801GBM), does not support 3Gb/s.
Intel Serial ATA Controller: Intel(R) 82801GBM SATA AHCI Controller
It is clearly shown in following part.
Current Serial ATA Transfer Mode: Generation 1
See the help of Matrix Storage Console for the meaning of "Generation 1."
A big thank-you to both GrandAdmiralThrawn and emoacht for your detailed explanations! So, I just need to use a new notebook! That gives me a good justification to persuade my wife. Haha. Thank you guys so much!