After some experiments with the test server here at home showed really dramatic performance improvements with Page Cache I was very keen to try it on our hosted live server. However performance is very poor. The results are much the same whether using the local filesystem or the database on another node. Load times for uncached pages are really slow at around 45 seconds. Once cached the pages load in 3-5 seconds unfortunately this is about double the time taken when the Page cache component is disabled.

Is there anything that I can try or anything that would help diagnose where the problem lies? Page load times on the test server when caching is switched on are about 5% of the original so the component obviously works well in the right circumstances & definitely works with our Joomla setup as the test server is a mirror of the live server.

Well, a few questions.
1. What version of PHP? (I have a feeling you're using php4... I HIGHLY recomend moving to php5).
2. What version of MySQL?
3. How much memory do you have available? I have a feeling that you're running into swap with PageCache, which is causing the slowdown...