For an office computer, these are awesome.  You could even throw last year's video card (or a 2 or 3 or 5 year old card) and make a halfway decent gaming rig out of it.  They're refurbished, and for these Optiplex that usually means you get a new SSD instead of a mechanical drive... and THAT means it's faster than it was new.  Quad-core with an SSD makes everyone happy.