Memory Issue after Upgrading to PHP 5.2

I had a site on centos 4.x that I upgraded to 64bit centos 5 to get mysql 5.

After I took care of a normal transfer between servers, I had two problems
1. Fuzzy_search using a deprecated - tried using ini_set('allow_call_time_pass_reference', 'True'); in settings.php but had to remove fuzzy_search
2. That left the big problem of overflowing 32MB of memory with an error that appeared to be in the views module. After following threads around similar issues (usually CCK and views), I upgraded to drupal 5.7 from 5.5, checked that I had no cck modules enabled (they exist in the directory), checked that I had the latest version of other modules.

I ended up increasing memory as recommended in settings.php
ini_set('memory_limit', '128M'); - thought I took it way too far. I have to get to a real internet connection later today to assess the sweet spot of enough memory to be fast for a single user but as small as possible.

Obviously this isn't a tenable solution. I haven't seen anything else on the site that would help me figure this out after 8 hours of digging.

Together with the move to Centos 5, I moved from a VPS with 2GB to a dedicated server with 4GB (and a db server with 8GB).... so I'm really

Any help is appreciated. I will be glad to share as much as possible to help nail this down.