Hi Kevin,

Thanks for the quick reply. To answer your question:

1) You posted this on SQL 2012 forum, but I thought Free Pages went away in that version
-----I think you are right.  Then question is:  the resource manager shows our 128G memory is all full, 6G is  for OS, Buffer cache is 44.6G,  procedure cache is 7.7G, what does the rest 76G used for?

2) How is your IO amount and performance compared to before this started happening?
  --- Our disk IO wait time is much higher than before. 

3) Are users complaining or things not happening in an acceptable (or roughly the same) time?
 ---   Yes, web pages ars slower, more slow queries in our log. And when the buffer was only 16G last Friday, our applications complains have many queries timed out.

4) Are you on a virtualized server? 
---    We are on a physical server with 16 CPU and 128G memory