M11X SSD issue...

I recently bought A Vertex 2E SSD for my alienware M11X R1 but for some reason it maxes out at:

READ: 222MB/S

WRITE: 80MB/S

when the vertex 2E is capped at:

READ 285MB/S

WRITE: 275MB/S

can anyone help with this? is it a chipset/cpu limitation? or is there something wrong?

Thanks.