I have a Mid 2011 27-inch top-of-the line iMac (quadcore 3.4GHz i7, 8GB ram), and it just seems so slow. It has a non-SSD HD, and perhaps it's just that I have become so used to SSDs. But I feel it has become slower. To start programs just take forever, and sometimes responses to key-strokes have a delay (the first few key strokes in a program). For example, to start MS Word 2016 takes 1 min! I ran diskutil to see if anything is wrong with the HD, but it found no errors. Is there anything I can do speed it up, except upgrading the HD (which I don't know is even possible)?