if it is not a good idea to put four chips in there, why would they have four slots?
I'm sitting here trying to come up with a really crafty reply to your logic, but my brain is fried and I'm stressed out because of work.
In short, your logic is flawed. Just because they give you the option, that doesn't mean you should necessarily take advantage of it. You're mixing 4 different (most likely) clock speeds. The RAM is only going to be clocked as fast as the slowest clock. I'm going to guess that the new chip you bought is basically shit quality. The latency is probably 3+ and it's dragging your other chips down with it.
Do some research. You'll find that it's not a great idea.
