MacBook 64-Bit???

Yes. The Core 2 Duo models are 64 bit!
Hope that helps.
🙂

"With its 64-bit processor architecture, the Intel Core 2 Duo can execute instructions in chunks that are twice as large (64 bits versus 32 bits), delivering advanced computational power to MacBook."

Some marketing guy outdid himself there. The real benefit is that 64-bits can address MUCH more memory than 32-bits, which is limited to 4Gbytes.

tele_player wrote:
Some marketing guy outdid himself there. The real benefit is that 64-bits can address MUCH more memory than 32-bits, which is limited to 4Gbytes.

But, of course, the chipset in Macbooks imposes an upper limit to the amount of memory that can be addressed, and that limit is 3Gbytes.

Actually, in the new models, I believe you can put in 4GB, but the MacBook will only utilize 3GB of that.

Main advantage for Core 2 based Macbooks is that they will be able to run 64 bit applications, e.g. 64 bit Java. Limit for MB is 2GB RAM currently.

a) lots of people running Java on the client? b) 64-bit java has much benefit when memory is still limited to 3 or 4G?

Now, if the 64-bit Java gets an advantage from something other than addressing, it could have done it on 32 bit processors, since they already had native support for 64-bit integer math, and floating point math has always been more than 64 bits.

a. For Macs after Leopard is released yes since built-in. b. Point is a Core 2 laptop can run the 64 bit application natively.

http://java.sun.com/docs/hotspot/HotSpotFAQ.html#64bit_description

Even Sun says 64-bit Java is mainly about addressing, and that it imposes a penalty for this, though improvements in compilers can mitigate this somewhat.

a) even if 64-bit Java comes with Leopard, it doesn't mean it will be used much, since programs need to be recompiled to use it and programs which don't need the large address space are better compiled and run as 32-bit. And anyway, I don't believe that client-side Java applications or applets are really heavily used.

b) even programs which need 64-bit for accessing much more memory will quickly hit the maximum memory which can be installed in most Macs, and a huge address space is useless when it means constant swapping to disk.

a. was an example (though I think you are misinterpreting Sun's kb article), point is that a core 2 will be able to run 64 bit java or many other 64 bit applications natively. b. problem with 32 bit on Mac OS is that it is outmoded tech, longer term 64 bit will be the only option.

No, I'm not misunderstanding Sun's article. We don't need to worry about 32-bit programs going away for at least a few years, and for current programs, 64-bit processors offer no advantage.

But yes, a Core2Duo can run 64-bit programs, and Leopard will support 64-bit GUI programs. It just won't matter for a few more years.

With Leopard and the brave new world of 64 bit Mac OS coming in a few months (not years) time I don't think you're correct. The OP can be relieved to know that they own a 64 bit capable Mac.

Third-party testing confirms what many have previously surmised. OS X runs faster in 64 bit for Intel Core 2 Mac!

http://www.geekpatrol.ca/2006/09/32-bit-vs-64-bit-performance/