Lazy Write Pages/sec is the rate at which the Lazy Writer thread has written to disk. Lazy Writing is the process of updating ...

Lazy Write Pages/sec is the rate at which the Lazy Writer thread has written to disk.  Lazy Writing is the process of updating the disk after the page has been changed in memory, so that the application that changed the file does not have to wait for the disk write to be complete before proceeding.  More than one page can be transferred on a single disk write operation.