4GB Memory Upgrade Worth it?

[gwsat]

would anyone advise just getting one 4gb card then running 6gb (2+4) as the mac only has 2 slots??

the apple web recommends running side by side..

Uneven sticks will slow the system down.

I recommend going for the extra 4GB.

I have a 4Gb module in one RAM slot and a 2Gb module in the other because 6Gb is the maximum RAM my Santa Rosa MBP can handle. It is my understanding that if the speed of a 2Gb module and a 4GB module is the same, the speed of operation will be the same as if both modules were 4Gb. Thus, it's important to insure that both modules are rated at the same speed. Otherwise the overall speed of operation will default to the speed of the slowest module.