I have about 1gb, but not the memory map error is my problem, the games just crashs ;D
Don't ask me why, but when i use an AddOn Manager to deactivate some AddOns it runs pretty smooth.
Nothing against Mod Folders, but i don't think that method isn't flexible enought for ppl with many addons. You should try the DKMM AddOn Manager, should be faster and easier to get rid of the AddOn errors.