SanDisk Extreme SSD - Write/Read slower than 500MB/s

I’m now using SanDisk Extreme SSD 120Gb (550mbs/510mbs) with P6X58D-E motherboard (SATA3 6GB/s)

After installed new windows 7, I found that the wrie/read speed of this SDD’s too slow. It couldn’t reach to 500mb/s

What Should I do now? How to make my SSD reed and write  faster ?

With your board, nothing you can do. The Marvell (so called) SATA III controller cannot provide full SATA III performance that you would get with an Intel SATA III controller, only found on Intel 6 and 7 series chipset boards.

The limitation of the Marvell controller is well known to SSD enthusiasts, and there is no fix for it whatsoever. The speeds you are getting now is the best you can do on the Marvell controller.

Thank you so much. I think i should get another motherbroad.

i also have very slow speeds with the same SSD 

i have updated the firmware to R211

 i use a Asus p8z77-v motherboard updated to latest firmware and have ACHI enabled.

and my speeds are 

nevermind i checked my connections and i had my SSD on a SATA 3gbs port instead of the 6gbs now im getting 433 mbs read