#2 Mar 02, 2013 17:12
I was working with a 240k posts / 40k categories system, and I confirm that b2evo loads all categories into memory. It even does it twice in some situations! I added a patch to v5 that improves categories loading logic.
The problem is actually in loading a lot of data into PHP memory, this particular issue has not been fixed since v2. However comparing to v2 there are a lot of other changes that improve page load time and minimize memory usage.
Yes, you will need to apply your changes to v5 after upgrade. Let me know if you need help upgrading or tuning up the system after upgrade.
Just a note, Wordpress or Joomla aren't optimized for large datasets too, they are even slower than b2evolution.