I have a Mid 2011 Mac Mini server (Quad core i7, 8GB RAM, 2 x 500GB HD, OS X 10.7.4) which at times runs unbelievably slowly. The machine isn't used as a server and all the server features are turned off. Most of the time I just have Chrome open (6 - 10 tabs / sites) and Excel. Sometimes popular web sites (eg Gmail, Google maps) take 10 seconds or more to load but loading the same pages on my old MBA (2009) which uses the same internet connection is almost instantaneous. I also find that gmail often becomes unresponsive (buttons don't work, can't type new mails, etc). The problem isn't confined to Chrome, Excel is often slow as well, eg it can take several seconds to load the 'Open Recent' list from the File menu. The Dashboard at times takes several seconds to render as do the Launchpad icons. Note this is an intermittent problem - as I type this the performance is fine. Any suggestions what I should look at to resolve the problem, perhaps a Mountain Lion upgrade? Geekbench (32-bit) gives a score around 8750 so it's not a CPU issue.