Just figured this out last night! My client was crashing every time I went to Open Base or any players base with a more advanced setup than myself. Didn't matter if it was by portal, on foot, or mappad. It would also crash if I went back to my base from a place like that. The PermGen setting is what finally fixed the problem. I had always left it at the default 128, but after changing it to 512 I haven't crashed once! Here are my current settings running perfectly: Hope this helps a few people!!!
Using Kirarara's Texture Pack I have never had a memory related crash using these settings. 7gb of ram is too high unless you have greater than 12gb.
Thanks for pointing that out! I really need to check out that Texture Pack sometime too. I have 12gb RAM and nothing else to do with it. =P