Look at a few different ways to identify memory pressure
(1) Ring buffers
http://thesqldude.com/tag/ring-buffer/
Which values of the returned results should I look at and how to compare them?
(2)
SELECT *FROM sys.[dm_os_performance_counters]
where
counter_name in('Page life expectancy','Memory Grants Pending')
and [object_name] like '%Manager%'
Same question - how to inprepet the results as good/bad