Otherwise just do a full upgrade and get DDR2.
256mb is plenty for XP. Just maybe not for the programs that you want to run in it. If you havent done one recently, then I'd first do a defrag and clean out the registry. If your computers still running slow, and using the page file all the time then get some more RAM. 512mb should be plenty as long as you dont play new games or use demanding graphics software.
On my notebook right now the used memory size is 249M, total Physical memory - 256M and free physical memory 90M - so it means that about 83M are in swap...
(and due to the physical memory size I prefer to run on this comp only Remote Desktop - so all programs I need are running on the main comp. The result is better than I try to start the simple IceBookReader directly on my comp for example (And I do not talk about some VC++ application or Photoshop)
Elysia: a total of 512 (if 256 has been enough so far) will be plenty until the OP is ready to move up to a new system. It would be wasteful to buy more than that especially since the cost of DDR1 is still high.
Here's what task manager says for my system. I currently have 392 MB of RAM (3x128 MB of PC-133), which is less than i would like to. I though about replacing one of those memory module for a 512 MB one but hey, i'm cheap, and can't find one for less than 10$. Note that my computer is 8 years old :).
Anyway. Here's the number. It says "122 MB of available memory, 178 MB swapped on the HD" (if i understand well), and there's really nothing much running on background. So i would say, 512 MB would be great, but 768 MB would be greater, etc.
No, the pagefile in task manager isn't what's in the pagefile on your disk, but how much memory is used in the entire system, RAM and on disk.
Really ? That's interesting.
Pretty much, stuff that is the oldest and most unused in memory gets swapped out, allowing you to keep launching more and more applications, but you take a huge hit on load time when you click on a completely paged program that takes up more than the memory left. Since it has to page something then unpage as much of the once completely paged program.
I want one of those so bad, but the price keeps me out of that market =(
However, I'm assuming that with such little memory footprint, Windows actually wants to keep some RAM free so applications that demands more memory can actually receive it directly instead of having to page out something to make room before granting the request.
Instead Windows might page out most unused pages to disk so as to keep some free. Makes sense, since it optimizes the speed of active applications.