This machine was recently upgraded to a 1TB HDD and 6G RAM. The operative partition on the HDD has been shrunk down to 150G or so and is about 28% full. The file-access performance improvement is quite impressive. Everything is running fine under OSX 10.8 Mountain Lion. However the weak graphics power is now sorely evident. I plan to remove the 1T HDD and replace with a 240G SSD in carrier. I have a Plugable Lay-Flat dock with USB connection. (Anticipating your suggestion - I don't want to use the 1T HDD as extra storage in this machine.) A. What's the "best" way to get the new disk in and migrate the current data to the new disk? (I'm fuzzy about how I should otherwise get a fresh OS install onto an otherwise pristine drive. I need some step-by-step help on this piece.) 1. ddrescue the HDD to the SDD? 2. use the SDD as a Time Machine drive? 3. Put the unformatted SDD into the machine and hope for the best? B. El Capitan 1. Should I go there or stay with Mountain Lion or something in between? 2. if so, I should upgrade the OS after the new drive is installed and working satisfactorily under 10.8, correct? Thank you all in advance for sharing your hard-earned knowledge!