New Macbook Aluminum... 3 gbs of RAM ok?

The little booklet that comes with the new aluminum Macbook says that if you upgrade your ram you should update each module to the same amount. Is this true? I haven't heard this sort of advice since DOS.

 

If you do use modules containing the same amount of RAM then you benefit fully from Dual Channel, which will give you a boost of around 5% when performing memory intensive tasks. This is true for any modern chipset.

 

I have 1x2gb and 1x512mb and I had no problems works very fast

 

You don't have to. Nothing will break and everything will work. However, matching pairs of RAM is encouraged for best performance. That being said, 3gb of RAM in single channel is probably better performing than 2gb in dual channel.

 

Even 3GB should be dual channel. Intel chipset should be able to run Async Dual Channel.

 

You are correct. But the performance hit of Asynchronous Dual Channel is still about 5% (on memory intensive applications).

 

But it doesn't use the intel chipset, all the new macbooks/pros use nvidia chipset + intel processor. I don't know if it can run in dual channel asyncronously, but it can atleast run in dual channel on 1gb each, so the remaining gig on the 2gb stick wont.