Could you post your "environment" information? (type environment in the intelligent search box).

There are many different causes for this.. A badly written add-on, a recursion in a structure, too many pages loaded at once.

Thanks for the reply Remo. Here is the environment information.

# concrete5 Version
5.6.1.2

# concrete5 Packages
Bookmarks (1.1.4), Clevyr Nav (1.0), Clevyr Tweets (1.0), CSV displayer (1.1), Cybersource Payment Form (1.8.0), Dojo Page Filter Pro (2.3), Easy Tabs from Stacks (1.0), Enhanced User List (1.5.5), Expand / Collapse (1.2.1), Force SSL (2.5), Google Docs Viewer (1.0), KS Discussion (1.0), Login (1.1), Mega Menu (1.5.2), MindNet Browser Update Notification (1.1), Page List Plus (5.5.0.0.6.8), Page Selector Attribute (1.1), Popular Pages (5.5.0.0.3.4), Popup (1.33), Pro Blog (10.8.0), Registrant Group (1.1), Slate Theme (1.5.1), Star Rating (2.0), tnSpacer (1.3), Trans Marine Save Area To Pdf (0.9.7), Zoom Image (1.0.3).

# concrete5 Overrides
blocks/discussion_topics, blocks/guestbook, controllers/register.php, controllers/profile, elements/editor_controls.php, elements/editor_config_blog.php, elements/profile, elements/discussion_reply_popup_form.php, elements/editor_init.php, js/merge-150-33.js, js/gil_register.js, css/merge-150-33.css, models/system, models/user_list.php, single_pages/members.php.BAK, single_pages/login.php, single_pages/register.php, single_pages/members.php, single_pages/profile

# Server Software
Apache

# Server API
cgi

# PHP Version
5.2.17

# PHP Extensions
apc, bcmath, bz2, calendar, cgi, ctype, curl, date, dbase, dom, filter, ftp, gd, hash, iconv, imap, ionCube Loader, json, libxml, mbstring, mcrypt, mhash, mime_magic, mysql, openssl, pcre, PDO, pdo_mysql, pdo_sqlite, posix, pspell, Reflection, session, SimpleXML, snmp, soap, sockets, SourceGuardian, SPL, SQLite, standard, suhosin, tidy, tokenizer, wddx, xml, xmlreader, xmlrpc, xmlwriter, xsl, Zend Optimizer, zip, zlib.

# PHP Settings
max_execution_time - 1500
log_errors_max_len - 1024
max_file_uploads - 20
max_input_nesting_level - 64
max_input_time - 1500
memory_limit - 1000M
post_max_size - 1000M
safe_mode - Off
safe_mode_exec_dir - /usr/local/php/bin
safe_mode_gid - Off
safe_mode_include_dir - <i>no value</i>
sql.safe_mode - Off
upload_max_filesize - 1000M
apc.max_file_size - 1M
mysql.max_links - Unlimited
mysql.max_persistent - Unlimited
pcre.backtrack_limit - 100000
pcre.recursion_limit - 100000
session.cache_limiter - nocache
session.gc_maxlifetime - 7200
soap.wsdl_cache_limit - 5
safe_mode_allowed_env_vars - PHP_
safe_mode_protected_env_vars - LD_LIBRARY_PATH
suhosin.cookie.max_array_depth - 50
suhosin.cookie.max_array_index_length - 64
suhosin.cookie.max_name_length - 64
suhosin.cookie.max_totalname_length - 256
suhosin.cookie.max_value_length - 10000
suhosin.cookie.max_vars - 100
suhosin.executor.include.max_traversal - 0
suhosin.executor.max_depth - 0
suhosin.get.max_array_depth - 50
suhosin.get.max_array_index_length - 64
suhosin.get.max_name_length - 64
suhosin.get.max_totalname_length - 256
suhosin.get.max_value_length - 512
suhosin.get.max_vars - 100
suhosin.log.phpscript.is_safe - Off
suhosin.memory_limit - 0
suhosin.post.max_array_depth - 50
suhosin.post.max_array_index_length - 64
suhosin.post.max_name_length - 64
suhosin.post.max_totalname_length - 256
suhosin.post.max_value_length - 1000000
suhosin.post.max_vars - 1000
suhosin.request.max_array_depth - 50
suhosin.request.max_array_index_length - 64
suhosin.request.max_totalname_length - 256
suhosin.request.max_value_length - 1000000
suhosin.request.max_varname_length - 64
suhosin.request.max_vars - 1000
suhosin.session.max_id_length - 128
suhosin.upload.max_uploads - 25

Wow, you've got a memory limit of 1000MB! That's a lot!

I can't see any add-on that caused a memory issue on my server but you're using a few add-ons I haven't worked with.

Are you by any chance familiar with raw trace files generated by xdebug? That's what I sometimes use to track down memory problems but it takes a while to get used to work with it.

thanks again for the reply Remo, No I'm not familiar with that.