plextor m6e m.2 incorrect/slow speeds

[yazzy11]

Recently bought this pci ssd and i'm getting slow speeds, I know for a fact this drive can get 600+ mb reads, but mine runs at 388 (using crystaldiskmark) all the time.

I cannot work out what I am missing/ have done wrong, here is my mb:

http://www.asus.com/uk/Motherboards/P8Z68V_PRO/

Please help

 

[yazzy11]

Anyone?