What is the best "Loading… Interval"?

[Plasma]

Right now it takes forever for new message notifications and alliance forum notifications to pop up. I find myself having to log out and then back in to manually refresh it. This gets frustrating. I also find other people responding to me straight away. I believe this may have to do with the selection of your "Loading… Interval" setting. I could be wrong, though, so I guess I'm just wondering what do I have to do to get my notifications ASAP?