Will the Vector work with my motherboard. I am assuming yes seeing as my motherboard has two SATA III ports.
Yes, it will work. SATA drives are backwards compatible so a SATA 3 (6Gb/s) drive will work on a SATA 2 (3Gb/s) port.
Connect your Vector to one of the 6Gb/s ports in AHCI mode for best performance.
Also, another question: What is the best way to use my old HDD for mass storage [Photos, Videos, Applications I rarely use] and my SSD for booting the OS as well as my main applications and games?