SATA controllers. Boot drives or Storage priorities

so I'd recently figure out that the top 2 SATA ports on my Z97 board are connected to a different controller, I believe its an intel PCIe lane or some gibberish. So my video editing rig has 4 WD 3tb red drives, 2 are in RAID 0 for fast video editing, and the other 2 are backups of that every once in a while. so Recently I rearranged the SATA configuration so that the RAID 0 was connected through those 2 faster SATA ports and noticed Immediate read and write performance increase. However, I don't know which would be more beneficial. to keep things as they are (my boot drive is a samsung 840 evo), or to move the SSD boot drive to the faster controller and keep the RAID 0 slower. Will the OS load faster depending on the Sata controller? any ideas?

Once your OS and applications are loaded thats it for the most part. But you could continuously wrtie to a storage drive.

yes you should considder moving your SSD to sata express. even good HDD's are only about 200gb/s read so unless your raiding 4 drives to 1 port I doubt you'll see any real performance boost.