SSD write speed less than 20mbps

[atptsoi]

Recently, after re-installing windows, my SSDs write speeds has plummeted, the read speeds were fine however my write speeds just went through the floor, even my HDDs write speed is faster. My computer is a Dell XPS 15z. Any idea how to fix this?

 

[DeaconFrost]

Do you have the Intel Rapid Storage Technology drivers loaded?