Mac Pro memory sizes

FROM : julius
DATE : Sun Jan 11 22:44:21 2009

Hi,
Not sure if I'm addressing the right list for this topic.
I'm just trying to get a notion of my memory requirements for a 
program I am designing to run on my Mac Pro. I will have large volumes 
of data passing through the program and I'm worrying about minimising 
page collisions

I've had a quick look on the net but can't find answers to the types 
of questions i'm asking below.
If anyone knows a good link I'd appreciate it.
I guess I ought to run some trials and no doubt will do once I have 
something running but someone ought to know the answers so ....
My questions are:

About This Mac says that I have 2GB of internal memory.
Is this 2GB of 64-bit words or 2GB of 8-bit bytes?
I appreciate that GB is Giga Byte but ......

Similarly with respect to the L2 Cache, I have 12 MB per processor, is 
that 12 MB by 8 bits or 64 bits?

In thinking about memory usage, where previously I would think of my 
program in terms of 8 or 16 or 32 bit words should I now be thinking 
in terms of 64 bit words?
That is, should I think of my available internal memory space as 
effectively being 500MB words?

Similarly, say that I had 100MB of 2 x 8-bit byte integers to save to 
disk, should I now think that this will be saved as 100MB by 64 bit 
(i.e. 8 x 8-bit byte) integers?
If it is 100MB by 64 bit integers then should I think of compressing 
the data so as to reduce bandwidth requirements?


Thanks
Julius



http://juliuspaintings.co.uk