Fatal error: Out of memory, but I do have plenty of memory (PHP)

Question

Since my question is getting longer and longer, I decide to re-write the whole question to make it better and shorter.

I run my website on dedicated server with 8GB

Answer 1

This is a known bug in PHP v 5.2 for Windows, it is present at least to version 5.2.3: https://bugs.php.net/bug.php?id=41615

None of the suggested fixes have helped for us, we're going to have to update PHP.