I'm running a forum with 900,000 posts, it's serving 70k-90k pageviews per day from a dedicated server, and I get the feeling that my site could be a lot faster. The server admin installed memcache and gzip in December with the following results:
-Google Webmaster Tools average load speed from 4.3 seconds down to 3.6 seconds.
-Page views (adjusted for visitors) up 14%
Over the past month, load time has been going in a generally upwards direction and is now at a ridiculous 4.6 second average load speed. We're receiving more visitors than ever before, but average pageviews are going down. Nothing else about the site has changed, no new plugins have been added.
Dedicated Server Hardware:
Processor: Dual Xeon E5520 Quad Core (Gainstown)
Memory: 8GB DDR RAM
Hard Drive: Dual 15,000 RPM 147GB SCSI RAID 1
I'm fairly sure that the server is overkill for the site, load average barely goes above 1 during peak hours.
Any ideas about what is killing my site's speed?