Switch to OSX 10.9, problem solved. My 2012 rMBP with top end specs is also sluggish on 10.10.3. Not sure what Apple is thinking. On the other hand I am still u

Switch to OSX 10.9, problem solved. My 2012 rMBP with top end specs is also sluggish on 10.10.3. Not sure what Apple is thinking. On the other hand I am still using my 2003 Panasonic CF 73. It's not quick, but for the limited tasks of automating my DSLR it works perfect.