Those sequential speeds are barely above a HDD.
You should be getting 250-270MB/s with SATA II (3 Gbps)

I will say try but couldn't see SATA operation mode in BIOS for your motherboard:
- edit registry to enable AHCI - AHCI : Enable in Windows 7 / Vista
- change SATA operation Mode in BIOS to AHCI (sometimes worded as Native).