Need to correct a couple things...
1. I don't understand 64 bit.
A. You don't HAVE to know about 64 bit. For most users of OS X, it won't matter.
The Application delivery mechanism for future OSX Snow Leopard apps will still be Universal Binary, which will include BOTH 32bit and 64bit code if available.
The default SL kernel is 32 bit which is more compatible. Note that the Snow Leopard 32 bit kernel can still run 64 bit processes that allows access to more memory, useful for some power users.
The only reason you have to know about 32bit or 64bit is if you are running windows.
With Windows there is a 4GB total memory limit with 32 bit windows. Mac OS is different. Even Macs running Leopard can contain and use far more RAM than the 4 GB limit the "32-bit" qualifier might seem to imply.
Yes, 64-bit kernel (K64) allows use of a very large number of RAM, 16 exabytes to be exactly, but do you have any apps that need more than a few GB of RAM?
With Windows you need to download a different version of the app / program / driver for different version of windows os. On Mac OS, you download 1 Universal Binary which will work on all 32bit and 64bit (if available) installs for that Mac OS.
Yes you are suppose to get higher benchmarks on certain artificial test for running K64, but in daily use you won't notice a difference for almost most users do on Mac OS X.
I need to correct a few things posted here.
There is huge misunderstanding by people concerning the difference between 32 bit and 64 bit operating systems. I am seeing it in many forums lately. And there is some confusion about physical and virtual memory.
The original poster has some information right but also wrong.
First, let me address the 32 bit information. Some of information is correct however they forgot a key phrase,
Virtual Address Space. The 4 Gb referred to is located in
virtual not
physical memory. In a 32 bit OS, processes are given 4 GB of Virtual Address Space to operate. However, the process my only use 2 GB and rest is system related. That is why you are seeing the trend to go to 64 bit in operating systems.
Second, now the beauty of 64 bit operating system. Why it is so much better is the Virtual Address Space. According to the information I found about OS X, it uses 18
exabytes of Virtual Address Space.
I believe that translates to about 10 terabytes +/- of Virtual Address Space. So, this allows each individual process more that enough room to work and play. That is the keep to understand 64 bit OS. You have a larger address space to work with.
Third, physical vs virtual memory. There is huge difference between physical and virtual memory. Physical is what you see and touch. Virtual is there but you can not see it but it is there.
You can install 8 GB of physical RAM into your system. However, your OS most likely use about 1 to 2 GB under normal load. And rest is truly free and can be used when needed. If your system used all of physical memory then your computer would not work.
Now the virtual memory is always larger than physical. That is Virtual Address Space allowing it to work and play better with others.
I just wanted to try to clarify this because there is so much confusion going on. I see to many incorrect advice and information given out.
