Considering that all the other components (memory capacity, processor speed, bus speed) can be configured nearly identically, just dropping a single OWC 6G SSD into your a 2012 MacBook Pro 15 can boost its performance on par with, or even a little past) the MacBook Pro with Retina Display.
But wait… the MacBook Pro 15” has two drive bays, each capable of running an OWC 6G SSD at full 6Gb/s speeds.
Two drives…
Same speed…
You know where this is going…
Yes, we decided to go all out and put the two drives in a Striped RAID to see how fast we could get.
With this setup, we averaged over 1000MB/s read speeds and write speeds that nearly hit 900MB/s. That completely blows the MacBook Pro with Retina Display out of the water!
OWC SSDs Make 2012 MBP 15″ a Speed Champ | Other World Computing Blog.
I E B A Tech Thoughts 