What do I need to use object cache?

Do you have object caching modules installed on your server (memcached or APC)?

I did not know I had to install just one of then. I’ve installed all ??

I guess that’s why my CPU usage is high now.

What should I do?

I’ve tried to uninstall all but one, here’s my compatibility check

Server Modules & Resources:

Plugin Version: 0.9.2.3
PHP Version: 5.2.10 (PHP5 required for Minify, Rackspace CloudFiles, Microsoft Azure support)
Web Server: Apache
FTP functions: Installed (required for Self-hosted (FTP) CDN support)
Multibyte String support: Installed (required for Rackspace Cloud Files support)
cURL extension: Installed (required for Amazon S3, Amazon CloudFront, Rackspace CloudFiles support)
zlib extension: Installed (required for compression support)
Opcode cache: Installed (APC)
Memcache extension: Not installed
HTML Tidy extension: Not installed (required for HTML Tidy minifier suppport)
Mime type detection: Not installed (required for CDN support)
Hash function: Installed (hash) (required for NetDNA purge support)
Safe mode: Off
Open basedir: On: /var/www/vhosts/lolhehehe.com/httpdocs/:/tmp/
zlib output compression: Off
mod_deflate: Installed (required for Page Cache (enhanced mode) and Browser Cache)
mod_env: Installed (required for Page Cache (enhanced mode) and Browser Cache)
mod_expires: Installed (required for Page Cache (enhanced mode) and Browser Cache)
mod_headers: Installed (required for Page Cache (enhanced mode) and Browser Cache)
mod_mime: Installed (required for Page Cache (enhanced mode) and Browser Cache)
mod_rewrite: Installed (required for Page Cache (enhanced mode) and Browser Cache)
mod_setenvif: Installed (required for Page Cache (enhanced mode) and Browser Cache)

If you have APC installed (which seems the case), then you should just be able to activate object cache by ticking the ‘enable object cache’ box in the w3tc settings, and select APC as your engine.