Very slow Silicon Power Velox V55 60GB

[npantos]

Today I bought a Silicon Power Velox V55 60GB SSD and instead of 550MB/s / 440MB/s I got this:

Motherboard is BIOSTAR TA790GX A3+ on AHCI mode in the BIOS (updated to the latest version)
I know I can get those max speeds, but this is more than bad
What should I do?

 

[Dereck47]

Your benchmark speeds are normal.

Your motherboard does not have SATA 3 (6Gb/s) ports, it only has SATA 2 (3Gb/s) ports.
http://www.biostar.com.tw/app/en/mb/introduction.php?S_ID=395#spec

 

[npantos]

Now I look specification at the website. Really SATA II. Strange, because Everest and another info program showed 6Gbit / s, so I thought it is the SATA III.