Windows XP x64 and 32-bit/64-bit programs memory use

[Alkali]

Greetings all.

I am about to buy some nice new ram, 2x1GB sticks of top end Corsair. My main reason for this is that right now my x64 install uses 1.3GB along with Far Cry, and more with BF2 and a couple other games easily take usage to 1.2GB. My development programs push me into the HDD space atm hehe... So, its a no brainer.

However, I would like to check what I think I know about the actual programs....

Are the following correct:
a). 32-bit games and programs can address 4GB Ram in x64. (I read 'only' 3GB somewhere online).
b). 64-bit games and programs can address up to the max the mobo can take up to 128GB physical whenever that day comes.

Im very tempted to get 4GB ram right now, as in my budget its perfectly possible. (No need to suggest anything about a new gfx card first or anything like that, thats also in the works). Is 4GB just going to cause more of a headache than help me?

Much appeciated

 

[imported_michaelpatrick33]

You won't notice any performance difference (other than a possible degrading if you are on an AMD system due to 1t to 2t timings with four double sided dimms) with going from 2 to 4 gigabytes of memory. If I remember correctly, native 32bit OS's can only address around 4gigs of memory space. I think Windows XP can address (or place) up to 2gigabytes at one time. In other words a 2gigabyte photoshop file for example. There are ways around this such as PAE but I am not too familiar with it.

Some more information

If you are gaming you would be far better off getting a better graphics card then more than 2gigs of memory at this point.