This is probably obvious but I just had to share it. In February 2013 I bought a new Dell Optiplex 9010 because my few years old at the time Dell could not handle ATX 2012 as we all remember that debacle. The 9010 had 2012-2019 ATX on it, and performed well, but slowed the last year. While doing a 2019 amended return I got a black screen of death. Was able to resurrect it but it kept happening. So my next thought (before reaching out to everyone here) was to get rid of ATX 2012-2016, services and all, since it's not really needed any more. Now the computer works great, ATX loads in seconds instead of minutes.
This year I purchased an Optiplex 7070 Micro which is about the size of what my wife calls "a Billy Sandwich." At least something good happened to me this tax season.