I posted another thread about upgrading my mac Mac Users -- mac mini or MacBook Pro for next upgrade? and I ended up buying a new mac mini, but I think I'm going to return it unopened. I found out my issue, so I share it here with anyone who is interested or who might have the same challenges. tl;dr Firefox is a pig on both my mac laptops for some reason. I switched to Chrome, and it's much happier. The long story: I upgrade to El Capitan a few months back and also LR CC this past week. About this time, my 2009 MacBook Pro (C2D 2.26GHz with 8GB RAM) came to a grinding halt. Memory was blowing past 8GB, which I attributed to the new version of LR, causing disk swaps and all sorts of pain. It had been slow, but this was a world of hurt. Over the last 2 days I've been doing (way too much) reading on mac memory management and other issues. That 8GB should actually be sufficient! My work laptop is also a Mac -- 2014 MBP with 16GB and it flies. Last night, I finally spent some time really examining the work laptop memory use while running. It routinely was running at 10GB RAM used, which is OK for that computer as it has 16GB, but I found that Firefox was eating 5-6GB of RAM on it's own! On my old computer, because Lightroom is so slow, I don't tend to close it, and FF was my browser of choice for years. So, in general, a lot of times both those apps are open. Since last night, I started using Chrome, and now the old 2009 is happy again Using about 5GB RAM total between Chrome and Lightroom. So if you have an older machine, and feeling bogged down, check and see if Firefox is the issue. Try switching to a different browser and see if that helps. Postmortem I'm going to return the mac unopened, and wait until the March Apple announcements to see what/if any new releases come out. The fact that Apple dumped a boat load of mac minis into refurb over the last few days, and took down the refurb page for the 2012 mac minis, leads me to believe they are either killing the mini (doubtful) or doing a refresh.