Want help confirming my suspicions! My work computer is a base 2015 Retina 27" iMac running Mojave (previously running Sierra). 8gb of ram, mechanical HDD. I forget the processor. I find the machine to be quite laggy and slow at times. The slow performance is not consistent, it comes and goes. Opening spotlight can take ~3 seconds and inputting text can be laggy. Right clicking a file can take a couple seconds for the menu to come up. Opening Photoshop CS6 can take ~45 seconds. Chrome loads slowly. Pages are slow to render. I primarily work in Chrome (email, github, several tabs, etc), Slack, Figma and very occasionally Photoshop (I usually have this closed). My guess is the slowness is coming from the HDD. The processors should be up to the task (easily I would think), and the ram doesn't seem to be a problem (I have checked the memory pressure and that seems consistently to be fine). I can't imaging the video card presenting an issue as well. Does that make sense? I'm a bit surprised at how laggy it can be even considering the mechanical HDD but would guess that adding an SSD boot drive would speed it up significantly. For reference, my 2011 27" iMac (with SSD) runs circles around this machine for regular tasks.