Response time varies considerably based on user.

I'm guessing that this has to do with the File Framework module.

Users with the same Role experience vastly different response times for a given node. For some it's a couple of seconds, for others it's a up to a couple of minutes.

The client and connectivity can be eliminated as factors, since I tested with multiple 'authenticated user' accounts on the same client and Internet connection.

Circumstances/observations:

• I've copied the site to a different server and am accessing it using its IP, as opposed to its production URL.
• The users who get quick responses haven't used or posted much on the site.
• The nodes that exhibit this tend to have file attachments or embedded images -- I'm using the File Framework module and turning off Preview didn't help.

I noticed this after moving the site from a server with inadequate resources (where all nodes were dog slow) to a one that has plenty. During the slow response, I see the Apache2 process taking up 40%+ of the CPU. Memory doesn't seem to be an issue, there's lots free.

PHP settings:
- PHP memory 128M
- APC enabled

mysql-slow.log shows _lots_ of queries, with different bitcache URLs like the following, for a single request...

# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 1  Rows_examined: 1034
SELECT g.uri g, s.uri s, p.uri p, o.uri o, t.uri type, d.lang, d.data FROM rdf_data_file d
            LEFT JOIN  rdf_resources g ON d.gid = g.rid
            INNER JOIN rdf_resources s ON d.sid = s.rid
            INNER JOIN rdf_resources p ON d.pid = p.rid
            LEFT JOIN  rdf_resources o ON d.oid = o.rid
            LEFT JOIN  rdf_resources t ON d.tid = t.rid
WHERE (s.uri = 'bitcache://fbc9586258dcc133ffc633f73625c5165785db2d') AND (p.uri = 'http://purl.org/dc/elements/1.1/extent')
ORDER BY d.did ASC;

...followed by...

# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 4  Rows_examined: 15
SELECT r.* FROM role r INNER JOIN permission p ON r.rid = p.rid WHERE p.perm LIKE '%access fckeditor%' ORDER BY r.name;
# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 1  Rows_examined: 4
SELECT s.name FROM fckeditor_settings s INNER JOIN fckeditor_role r ON r.name = s.name WHERE r.rid='2';
# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 3  Rows_examined: 3
SELECT * FROM fckeditor_settings;
# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 38  Rows_examined: 1144
SELECT  DISTINCT(n.nid) FROM node n  INNER JOIN node_access na ON na.nid = n.nid WHERE (na.grant_view >= 1 AND ((na.gid = 0 AND na.realm = 'all') OR (na.gid = 2 AND na.realm = 'node_privacy_byrole_role') OR (na.gid = 3 AND na.realm = 'node_privacy_byrole_user'))) AND (  n.status = 1 AND n.nid IN (199, 242, 243, 263, 244, 200, 10, 196, 195, 194, 17, 241, 258, 267, 262, 257, 278, 279, 282, 203, 204, 119, 110, 62, 205, 206, 54, 207, 183, 56, 161, 211, 208, 65, 158, 245, 260, 261));
# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 7  Rows_examined: 11
SELECT v.*, n.type FROM vocabulary v LEFT JOIN vocabulary_node_types n ON v.vid = n.vid ORDER BY v.weight, v.name;
# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 229  Rows_examined: 932
SELECT t.tid, t.*, parent FROM term_data t INNER JOIN term_hierarchy h ON t.tid = h.tid WHERE t.vid = 2 ORDER BY weight, name;
# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 8  Rows_examined: 16
SELECT * FROM menu_custom ORDER BY title;
# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 10  Rows_examined: 1411
SELECT  DISTINCT(nc.nid) FROM node_comment_statistics nc  INNER JOIN node_access na ON na.nid = nc.nid WHERE (na.grant_view >= 1 AND ((na.gid = 0 AND na.realm = 'all') OR (na.gid = 2 AND na.realm = 'node_privacy_byrole_role') OR (na.gid = 3 AND na.realm = 'node_privacy_byrole_user'))) AND (  nc.comment_count > 0 )ORDER BY nc.last_comment_timestamp DESC LIMIT 0, 10;
# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 7  Rows_examined: 14
SELECT name, title, type, visibility, weight FROM profile_fields WHERE visibility IN (2, 3) ORDER BY weight;
# User@Host: du[du] @ localhost []
# Query_time: 0  Lock_time: 0  Rows_sent: 11  Rows_examined: 666
SELECT * FROM menu_router WHERE tab_root = 'node/%' ORDER BY weight, title;