2x2GB vs 2x1GB for gaming? Your experiences?

[Clunk]

I'm interested to hear from anyone who has 4GB in their gaming rigs and if they can see a difference to their game play.

Stuff like frame rates, loading times and anything else you can think of that makes 4GB better than 2GB.

If you have any results for 2x2 and 2x1GB, then post them in this thread please

Ideally, what I want to do is build up a bit of a database of games and hardware that work better with 2x2GB of memory installed.