My 2010 MacBook Pro was starting to show its age when editing RAW photos. Not surprising, since each photo is about 25MB in size! I ordered a Samsung 840 EVO solid state drive to replace the 7200 rpm spinning platter I had in there. I forgot to measure the speed before but I figure it was around 140MB/s read/write. Now it is around 260MB/s and everything loads so much faster!
The computer boots from cold in 14 seconds – woo! Photoshop loads in about 6-7 seconds, and Safari practically instantly.