MacBook Pro 64 bit??

[tji]

The new MacBook Pro has the Core 2 Duo "Merom" processor, which supports the EM64T mode. But, in all of the marketing material, any mention of 64 bit is conspicuously absent. Anyone know why?

Some articles I have read say that it uses the Intel 945PM chipset, like the iMac, which does state 64 bit support on its marketing pages.

Both the iMac and the MBP have an upper limit of 3GB of RAM. I understand that this is a limit because of the memory address space used for I/O operations. This 'virtual addressing' used for I/O cannot also be used for RAM. But, when the system is in 64 bit mode wouldn't this limitation go away? With the huge 64 bit address space, the hardware I/O space can be well outside the usable RAM space. Is there some other limitation in the chipset, or will Leopard be able to take advantage of a fully populated 4GB memory space?

It's also kind of odd that the leopard 64 bit page ( http://www.apple.com/macosx/leopard/64bit.html ) specifically mentions the Xeon / Mac Pro, and not the iMac or MBP. But, the 64 bit mode of the Xeon and the Core 2 Duo should be equivalent.