4GB Dual Channel (2x2gb) Vs. Single Channel (1x2gb + 1x4gb)

Hello,

I'm aware that threads similar to this one have been posted, but not quite what I'm looking for.

I have an older Macbook Pro that was produced in 2007. while apple claims it supports up to 4gb of ram, outside testers have found that it can support 6gb of ram. Unfortunately, the ram bus does not support more than 667 Mhz, while the FSB supports up to 800mhz. I currently have 2 x 1gb and I'm planning to upgrade that. My question is will I see better performance from using 2x2gb ram modules running in duel channel or would i be better off forgoing the dual channel speed in lieu of 1x2gb and 1x4gb ram modules running in single channel?

cheers!

Ian