I must have forgotten to hit the "post" button last night. Apologies to those I referred to this thread before I actually posted. :)
I believe I am seeing the same thing. Any access -- just landing on the home page -- tries to eat 256MB.
Ubuntu 9.04 x64 512MB VPS
PHP 5.2.10 / Suhosin
phpinfo(): /etc/php5/cgi/php.ini with memory_limit=64MB
wp-config.php: define('WP_MEMORY_LIMIT', '64M');
Note that regardless of how low I set memory limits (simultaneously in php.ini and wp-config.php) my server log indicates that wp-admin.php is trying to grab 256M, as described by Helpy earlier in this thread.
Symptoms are intense disk thrashing from a single pageload, leading to failed and partially rendered pages and server timeouts. Unusable.
I tried very hard to follow the directions to install WP3, but maybe I did something wrong. Any ideas about what I should check?
Or is it just a fact of life that WP really needs 256MB to be happy even with no plugins?