AKA Classified 3-way SLI. I just got a Samsung 860 EVO 250GB SSD, and having problem with its performance as seen in the pic below. Been scratching my head since this mobo supposedly having 2 SATA 3.0 6Gb/s ports with Marvell controller-stuff. AHCI has been enabled and I ran the test both on 4.3GHz and stock settings of the X5690. I have 2 sticks of 8GB DDR3 running dual channel as well. 
Strange thing is the Samsung Magician fully detected the drive when I first plugged it in, but after I migrated the OS from my old SSD it doesn't anymore, and even now after a clean install. 

the_Scarlet_one
Have you checked for updated firmware and the most recent Samsung driver?

Thank you for replying. 
I believe my whole system is up to date in term of softwares. Samsung doesn't provide driver for the 860 for some reason. 

Correct me if Im wrong, the user manual says this mobo can support up to 600MBps, and I will understand it as 600 megabytes per second or 600 MB/s as its supposed to be. But there is another rev of this mobo which is the 141 GT E770 *A1* that I quote EVGA "has a better SATA interface that support fully 6Gbps" which still equal 600 MB/s.
I'm a little confused here. So there is a better version of the controller that literally has the same specs? If that's the case, can I go around this by using add on pci/pcie SATA controller?

dracuto1007
AKA Classified 3-way SLI. I just got a Samsung 860 EVO 250GB SSD, and having problem with its performance as seen in the pic below. Been scratching my head since this mobo supposedly having 2 SATA 3.0 6Gb/s ports with Marvell controller-stuff. AHCI has been enabled and I ran the test both on 4.3GHz and stock settings of the X5690. I have 2 sticks of 8GB DDR3 running dual channel as well. 
Strange thing is the Samsung Magician fully detected the drive when I first plugged it in, but after I migrated the OS from my old SSD it doesn't anymore, and even now after a clean install. 

That looks perfectly normal for X58 3rd party SATA. They are not native so are a bit slower than native chipset SATA III. You're better off using the native intel ports. While not quite as fast speed wise as the 3rd party SATA III ports, the latency is far lower. Unless you spend all day transfering huge files, system response and performance will be better using the native ports. Also, if you do not need to use the Marvell ports, disabled them in the BIOS. The system will boot faster not needing to initialize them.

Buy a old LSI raidkontroller then u get full speed and boot win
I have 4 ssd in raid0 1500/1900mb/s top
No hard setup, works perfect with bios
LSi 9260 is a good one.