The speed of my site is random sometimes it loads fast sometimes not

I contacted my hosting provider (123-reg)

who came back with the following answer:


Thank you for contacting 123-reg on the 19th April 2012.

Using caching within a shared environment can have an adverse effect in that it slows the performance of the site rather than speeding it up. Can you please confirm if you have any caching plugins installed within your website. If so, can you please disable this function to allow us to troubleshoot your website performance issue further. The following article can be of assistance if you are using Wordpress or Joomla:
http://www.123-reg.co.uk/support/ans...software-3405/

If we can be of any further help with regard to this or any other matter, please do not hesitate to contact us.

Kind regards,

Sorin
123-reg



Is the above statement true? is there anything i can disable?