HI, I have iMac 27” mid 2010 2.8 ghz intel core i5 8gb 1333 mhz ddr3 Ate radeon hd 5750 1024 mb After installing high Sierra, editing photos takes too much time, and stop response sometime. It happen espeailly when I edit Raw format file. So I'm thinking to upgrade my iMac. Please let me know what(Ram/SSD/...) will make most cost effective and best performance upgrade? And let me know if it is easy to upgrade myself. I think I'm handy. however I don't have experience to upgrade iMac myself. Thanks.