SSD only running at 3.0Gb/s Cannot get SATA 3 speeds

[Ultraviolet]

This is doing my head in and so frustrating but it's something that I'm running out of options on so appreciate all suggestions:

 

I have a Samsung 850 Pro as my boot drive and it works fine, samsung Magic reports the interface is running at 6.0Gb/s and the reported speeds back this up so all is well.

I have a spare Samsung 840 Evo that I am dumping video too but the speeds are only reporting at SATA 2 - checking in Samsung magic their is a yellow exlamation mark that when you click it says SATA 3 is Available, HOWEVER I cannot for the life of me get this drive to run at SATA 3.

 

My motherboards is a ASUSTeK COMPUTER INC. Z87-K which has six SATA 3 connectors, I have the latest bios installed AHCI is activated and trim is running.

The drive has the latest firmware and I have the latest version of Samsung Magician, I've swap tested the sata cable and STILL cannot get this drive to read as SATA 3.

 

ANY help with this would be great as I'm completly out of ideas at this point and don't know what else I could do :(

 

THE 850 WORKS FINE HOWEVER.....

 

 

 

[Mindovermaster Moderator]

I was going to say, update the firmware, but as you say, its on its latest.

 

Is there any settings on the board's BIOS for this? Maybe you need to set it to SATA3, being it is a secondary drive, or something? Only thing I can think of.

[Ultraviolet]

Well I found it it WAS  problem with the cable...apparently, even though I swapped it with the one that was already working...go figure. Something funny is going on but whatever, it's working now with the new sata cable so that works for me! thanks mindovermaster