As a simple example, running the following script alongside mongotop will show no increase in top statistics: db.toptest.insert({a:1}); for ( var i = 0; i < 100000; i++) { db.toptest.findAndModify({ query:{a:{$gt:0}}, update:{$inc:{a:1}} }); } mongotop will consistently show ns total read write 2016-06-08T09:59:48-04:00 test.toptest 0ms 0ms 0ms Meanwhile, running the similar script with update instead shows an increase in top statistics: for ( var i = 0; i < 100000; i++) { db.toptest.update({a:{$gt:0}}, {$inc:{a:1}}); } ns total read write 2016-06-08T10:04:47-04:00 test.toptest 197ms 0ms 197ms