The SSD is prepared for UEFI AND LEGACY boot. THIS SSD NORMALLY WORKS ON BOTH BOOT SYSTEM BUT IF NOT YOU MAY HAVE TO CHANGE BOOT ORDER TO UEFI OR LEGACY. AFTER 2013 IS UEFI BOOT APPLY. YOU WILL NOT GET ANY WARNING!
My Mac starts up in a quarter (or less) of the time and so do the bigger programs (browser, Skype etc). Just know how to load the contents of your previous hard drive and said drive's name.
Working for two months now, no problems.