Hi fellow macies . This is my first post on Macrumors and i need some help. I am currently running a OWC mercury extreme 120gb as my main operating system HD on a 2012 2.7ghz I7 macbook pro (non-retina macbook 9.1) with OWC 16gb 1600mgz ram. I want to add additional storage in my laptop via the optical drive so i need some help choosing what type of HD to put there. My question is in regards to speed. will there be any difference in speed if i install a regular 750gb HDD drive vs. a 240gb SSD drive as a storage? Someone told me that there wouldn't be noticeable difference because the files i want to store wouldn't come directly out of the drive itself but it would be stored in the cache and that it would load the files (songs,movies,etc.) in the same speed or pretty close to it. I do a lot of cpu intensive audio editing and music production so basically my logic pro and ableton live are running only on the operating system and i would like to add my sound libraries and sound banks on the secondary storage. would i notice any difference in loading samples and sounds from the HDD vs. the SSD in the optical bay? Thank you for your responses in advance.