Need advise on Mac Pro Configuration

Hi, I need advise on mac pro configuration.

I am a print designer looking to do motion graphics work. Hence, looking to purchase a machine that can handle the following programs: After Effects, Premeire Pro, Cinema 4D, and possibly Maya in the future, Photoshop, Illustrator, indesign, etc. Not in the mg industry yet. but looking to learn/sharpen my skills in using 3d programs and AE so can create a reel to get work in the industry. I want a machine that can last for the next 6 years with expandability. So don't want an iMac. I can't afford to have a fully loaded machine. I do plan to have the other bays installed 1 or 2 years later.

This is what I am thinking of getting
Two 2.4GHz Quad-Core Intel Xeon “Westmere” (8 cores)
1TB 7200-rpm Serial ATA 3Gb/s hard drive
24GB (6X4GB) Memory
ATI Radeon HD 5770 1GB
One 18x SuperDrive

My question: with just 1 HD bay in use, is the machine able to fully utilize all 24 gb of memory? or is the machine only able to process 4 gb at a time max; putting 20 gb unuse until i have the other bays installed?

the reason why I am looking at 24 because I don't want to get 2gb of memory stick, then later have to replace it with 4 gb stick in order to get more memory since with the 2gb maximum memory is 16 gb.

Any advise is appreciated! Thank you in advance for your help.

Are you talking about hard disk memory or ram

Macs can access that sort of ram even in 32 bit mode, 32 bit apps can have 4 gig ram each, while 64 bit apps can get as much ram as you have available to them

More info on memory management here

http://iphone.appleinsider.com/arti...bits_santa_rosa_and_the_great_pc_swindle.html

If by the sounds of things you are heavily into graphics design and print, yes the 24GB is the go. You will get six years use no trouble.

Thanks for responding. I will be using CS5 adobe programs. So it uses 64 bit. I think I am referring to RAM and not hard disk memory.

So from what you said about the 64 bit, it sounds like it doesn't matter how many bay I have installed. The more bay I have access the more places those 24gb will have to split up. Is this correct? Or is it that the number of bays and the amount of ram has nothing to do with each other?

Sorry, if this is not clear. I just want to make sure that the available rams won't go to waste when only 1 bay is in use. If it goes to waste, then I rather have 2 bays and 16gb of ram. I don't want to do this, but I can't afford to have 2 bays installed with 24gb of ram. I will have to replace those memory sticks with 4gb sticks when I have the need and money for it.

On another note. The graphics card that comes with this configuration is pretty good for motion graphic work right? or do i need to get a nvidia?

Thanks