My blog (hitormiss.org) has gone from using around 60 queries (taking less than 1 second) per page load to using around 770 (taking 3 to 10 seconds to generate the page). I used a debug statement in wp-db.php to determine that the WP code was requerying the database each time it used an option value (from wp_options). Shouldn't it be caching those variables?
I've reloaded all the core WP files and tried using different themes, but I'm always getting a massive number of queries hits.
Note: I do run another website on the same account which uses the MySQL server (but doesn't use WP code).
Any ideas to fix this?