My mid 2011 i7 /16gb iMac has worked pretty flawlessly since new but now unable (I think) to update to the latest Mojave OS and it puts the thought in my mind that it is time to replace it. So mine was purchased prior to SSD and hybrid drive wide availability so has the standard 1Tb fixed hard drive and so is slow to boot and recently clearing up, moving large folders can be annoyingly slow. I use Lightroom and Affinity for photo editing and the usual office / Mindnode / safari for normal day to day use. I understand that it'll boot faster and apps will load quicker - but my question is will I notice much of a difference after booted with one of the latest mid range 27"? I'm not into opening up and adding an internal SSD. Grateful for your thoughts.