When playing Playstation Home, every so often theres a metallic clunking noise in the backround, whats it for?

May be...

I know what you're talking about. It's the noise in the game not on the PS3, right. I hear it too. It's like a taxi cab meter rolling from time to time...hahahaha. I guess it's just an internet or server connection related noise. Nothing to worry about.

Were you in or near the new XI space? Because for some stupid reason the home staff thought it would be cool to add a backgroundd song to a space, but one that can be completely annoying at times. It has randomly appeared for me when I am in the XI space. It truly is annoying and wish it wasn't there.

Are you talking about a clunking money kind of sound?

That is how many points you will have earned. Sony MIGHT be going to make use of virtual money in the future and you taking part in the Open Beta will help alot. So its a "background reward"

It's not final though.

This is what I have heard.

its just the lens mover that holds the lens this prob could b solved if u dust off the inner base regularly but this prob never occurs in ps2

possibly your hardrive is heating up.

i havent had it happen to me but i always keep my cooling fan on