I've decided to buy a new iMac before the end of the tax year, and am now deciding whether I should buy another raid DAS which would connect by USB3 or Thunderbolt, or a Raid NAS. The large multi layered files can take up to 20+sec to save, this is something I'm not used to as the smaller 5D2 files would save 'instantly' to the internal or external storage. The major problem now is saving image files to my external storage (WD Raid firewire800 connected) after work in PS. I've upgraded the mac's internal storage from a 1TB HDD to a 500GB SSD and the mac works really quickly now. My recent acquisition of a 5D4 with its large files and my 2010 iMac with USB2 and firewire 800 has highlighted how slow moving files from mac to external storage can be.
