Wordpress and wp-cache problems

I've recently done a one click install of Wordpress 2.3.2 under PHP 5.2.2 with extra web security.

It works but is rather slower then I would like and so I looked to activate the wp_cache plugin.

Unfortunately that slows the site up much more. Pages that were coming up in 5-10 secs suddenly take a minute to arrive. When I disable wp_cache I get back to where I was and pages load up again in 5-10 seconds.

A few people have had problems with wp_cache and so I tried WP Super Cache, but again the same things happens - very, very long page load times.

I've looked in the Dreamhost wiki but nothing in the Wordpres section seems to cover this. But I may be missing something - Wordpress and the Dreamhost panel is all pretty new to me.

Has anybody seen behaviour like this and found a way forward?

Thank you

I just installed it to test in the same environment you stipulated. It worked without any delays.

Perhaps the issue might be caused by a plugin that reacts badly to Mod_Security?

You could test by temporarily disabling it in your WP folder.
http://wiki.dreamhost.com/Mod_security

After you turn on wp-cache the 1st time you visit a page is when the cache for that page is generated, so it will take longer than normal.. The 2nd time you visit that same page the cache will be working, and it will be faster.

Verify its working by viewing the source code for the page and looking at the very bottom for something like

< !-- WP-cache served in 2 seconds -- >