MacBook Pro 4GB Memory question for a guru

I searched the forums prior to this post and read what I found regarding the RAM limitation. I feel this post is new question.

I have a 15" MacBook Pro 2.16 GHz Core 2 Duo that I bought in January of 2007. It came stock with 1GB of RAM. I see that Apple states the max of 3GB for this machine and from what I read here and on the internet, the machine will take 4GB, but only show 3.3GB or so due to the Intel chipset limitation.

I recently installed 4GB in it and I am really puzzled at my machine. Not only does it show 4GB in "About This Mac" and in the System Profiler (which from what I read is normal) BUT it also shows 4GB in Activity Monitor.

Now from my reading the Activity Monitor should show the 3.3GB, but mine shows 4GB.

I have two thoughts on the issue. One is that possibly a firmware or software update along the way raised the limitation and it hasn't been mentioned.

Two is that there was a silent hardware revision and that some of the machines that are supposed to be limited to 3GB are actually truly capable of 4GB.

My question: Can someone explain to my why my machine shows all 4GB in use when it should be limited to the 3GB?

Puzzled MSgt

The question is how much does it utilize? When I put 4GB into my (late 2006) Macbook C2D, it saw all 4GB, but would only utilize 3.3GB.

That said, you will still see better performance with 4GB (matched pair of 2GB modules) than you will with 2 or 3GB.

If you can find a way to try and utilize all 4GB and see where it caps out (something really complex in Illustrator/Photoshop sounds like it should do the trick) and post results, I would be interested in how it does.