Slowness

I’ve recently installed the plugin and it seems to slow the site down greatly. Is there something I can do to remedy this?

It goes from factional second loads to upwards to 20 seconds a page load if lucky.

The server is dedicated in rack has a 4core 3.2ghz xeon and 16gb ram. It’s not a low end machine or lower end kvm vps.

Any advice would be appreciated.