I have windows xp 32bit running with a c2d 6300 and a 8800gts and was wondering about how much memory to use. I currently have 2gb (2x1) of crucial ballistix ddr2 800 running in dual channel mode. I know xp 32 bit has the 3 or 4 gb ceiling, will i gain any performance if i install more memory? I have another 2 gb of the same ram. If i install just 1 more will my performance drop because it wont be running dual channel?

Erik

Depending of what program you currently use, you may or not need more than 2GB. One thing to look at is your swap file usage.

Because you have in hand the extra memory, what don't you just try it?
Yes, 1 should slow down and I would install both and live with the fact that only 3.2 will be usable.

If you decide to move in the world of 64bits, your system will be ready.
I currently have Vista 64 bits and happy with it. My system never been better since I moved from Vista 32 2GB to Vista 64 4GB!!! I even reduced the Swap File to 512MB.

Short answer: Enough.

Long answer depends on how many tasks you have running at one time, and how much memory they use in total.
I would agree with loneeagle; since you have the memory, try it. I can not imagine a scenario where 4gb could hurt you in any way. XP was built when memory was expensive so it tries to make room for what you might load by clearing out pages to the swap file in anticipation of need. I theorize that having 4gb (or 3.3gb) available might keep XP from working the swap file so hard since it knows you have plenty.

Vista, on the other hand will try to load things that it thinks you are going to need in advance. It will appear to be using more memory, but it really is trying to make better use of what it has. I, also am very happy with 4gb and Vista-64.

Actually, you're already at the limit of conventional (32bit OS) memory. Both XP and Vista 32bit OS can't use above 2 GB of physical memory, due to virtual memory addressing issues. The so-called "4 GB barrier", which is the addressing limitation of 32bit OSes, has to include not only Physical memory, but also virtual memory which partially includes the swap file. You can't really get around this, without specialized applications and software.

More info: http://www.anandtech.com/gadgets/showdoc.aspx?i=3034

So, unless you're planning to switch to a 64-bit OS, you're fine right where you are at.

errr i have 3gb 2x512 and 2x1gb and windows adresses it all

An individual 32 bit application is limited to 4gb of address space. It gets even less because windows needs to reserve some (2gb) of it. There may be multiple applications running, each looking at their own 2gb, and sharing windows 2gb.

This virtual address space must be backed up by real memory in order to run. Again, because of 32-bit addressing this is limited to 4gb.

So, with several applications running at once, more than 2gb can be useful to keep in memory more of what is needed to back up the virtual address space memory of several tasks.

It would be useful to read the link posted by rripperr. It describes the problem of some games that want to move the 2gb line between windows and the application to give the application more address space. That does not mean that 4gb is not useful.

Indeed, if you read further into the article (and there's 2 parts), you find out that if you manually decrease the "swap file" size too much, it can actually DECREASE performance as XP tries to "organize/prioritize" the swap file info. So for most pratical puposes, 2 GB is the optimum amount of physical memory. Big enough to still be fully utilized. Once you go over 2 GB of data, XP (and Vista to a certain degree) start swapping more and more data to the disk, so that physical memory is not overloaded. This is a hard coded system behavior, you can't really get around it.

This doesn't mean XP or Vista can't "see" or even address over 2 GB of physical memory. It just means it will not be utilized as fully or effectively as 2GB of memory.

Thanks fellas for the quick response! I think i will just sit tight with my 2gb right now and maybe just be ready whenever i decide to pull the trigger with vista.

Erik