I recently installed a fresh copy of windows & 64 bit onto my Samsung 840 evo 250 GB SSD. I additionally have 2 500 GB HDD in raid 0. consequently my MB is running in raid mode and not AHCI on account of the HDDs. When I use Samsung's packaged software (Samsung Magician) it "sees" the SSD but tells me "AHCI is disabled for one or more connected SSDs. System boot in AHCI for best performance." I am not sure what to do, go back to the bios and change to AHCI? or leave in raid zero. the Samsung Magician is reporting advertised seeks and read times as well writes.