On the server with Linux OS if you observe that lot of the memory is being cached.. Like shown below

total used free shared buffers cached
Mem: 12155 11741 414 0 303 5830
-/+ buffers/cache: 5608 6547
Swap: 24999 0 24999

You can free up the memory cache using the below commands
To free pagecache:

[root@Supp0rtAdmin]# echo 1 > /proc/sys/vm/drop_caches

To free dentries and inodes:

[root@Supp0rtAdmin]# echo 2 > /proc/sys/vm/drop_caches

To free pagecache, dentries and inodes:

[root@Supp0rtAdmin]# echo 3 > /proc/sys/vm/drop_caches

You can atomize this task by simply creating the file Clear_Memory_Cache.sh with the following code in it

[root@server123]# cd /etc/cron.hourly/

[root@server123]# vi Clear_Memory_Cache.sh

#!/bin/sh
sync; echo 3 > /proc/sys/vm/drop_caches

And restart crond dameon

[root@server123]# /etc/init.d/crond restart