To optimize and accelerate website performance you can use an opcode cacher such as Xcache. Bellow are the steps I took to get this installed.
Step 1
Install xcache
apt-get install php5-xcache
Step 2
Update config for xcache
sudo nano /etc/php5/mods-available/xcache.ini
Set a username and password
[xcache.admin]
xcache.admin.enable_auth = O
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