SSD on MSI P6N SLI Platinum speed issues

[Snake_A]

Hello my current setup is as follows:

Q6600 cpu
MSI P6N SLI Platinum mobo
4GB 800mhz ram
R9 280x Vapor X GPU
Samsung 840 Pro 256gb SSD
Thermaltake 750w PSU

I know that my mobo-cpu are quite old, but i was just wondering why Samsung Magician cant communicate with my 840Pro (tried win8.1 + win 7) and why my ssd speeds (read/write) are less than150MB/s while the mobo supports SATA II which speeds up to 300MB/s
.
I had my ssd on a laptop and samsung magician software was detecting it properly.

Thank you for your time!

 

[mad-max79]

There are some issues with old Nvidia based boards which sometime only run with SATA 1.5 Gb/s. But shouldn't make big problems, because the important IO/s are usually below this barrier. The performance is only low for sequential operations, which don't occur so often.

 

[Snake_A]

There are some issues with old Nvidia based boards which sometime only run with SATA 1.5 Gb/s. But shouldn't make big problems, because the important IO/s are usually below this barrier. The performance is only low for sequential operations, which don't occur so often.

Thank you for your reply!

Thats fine then, but what about Sasmung Magician software which cannot communicate with my ssd? Is this normal with old Nvidia based boards?