17" iMac RAM question

I have a 17" 2.0 GHz C2D white iMac, now I know it can only recognize 3 GB of RAM, but with prices the way they are I'm thinking about just putting 4 GB (2 x 2 GB) in it. My question is do I get the benefits from matched pair from that? are there any other pros or cons to putting in 4 GB instead of 3 GB (1 x 1 GB, 1 x 2 GB)?

TY, so my understanding from that is that there is a performance boost when using 2 x 2 GB instead of 1 x 1 GB, 1 x 2 GB, even when 3 GB is the max supported RAM. Even though it's only a slight increase it would be the way to get the most of out my RAM. Guess I'll be ordering 2 x 2 GB sticks next paycheck. TY again