You didn't mention which operation system was being used. It's not so much a matter of EQ2 supporting the memory amount. It's a matter of the operating system itself supporting it correctly. Microsoft Windows XP Home, Microsoft Windows XP Professional and Microsoft Windows Media Center all require
PAE to be set. Luckily that's done automatically if you install the
AMD dual core patch fix. From what you wrote you had already done this. You mentioned running one memory test on the system. Have you also downloaded and ran
MemTest? There may be an issue too if the memory you have installed are not exact brand and model matches. This can cause timing issues.