You don't have to go as drastic as DSL, something with Xfce would be just fine. Also, a lot of mainstream distros have a lot of services running to make the end user's life as easy as possible, whether they need the services or not.

I'm using about 600mb of my 2gb of RAM in this laptop at the moment, and I have quite a bit running. Switching to Firefox 3 was a major help, they fixed a lot of the memory issues 2.0 had.

As said by others, Mandriva has bad reputation about this point because a lots of things are loaded at boot time. You might try Freeduc http://www.ofset.org/freeduc-cd-presentation

Use a low-resource Gui. Linux itself is quite low resource, but linux itself is a kernel and not much else. The stuff you put on top to make it into a friendly computer use a whole lot more resource.

So, you want to avoid KDE and Gnome, and think more in terms of Xfce, Fluxbox, Enlightenment,... As these are often either 'love it or hate it' experiences, you will need to try them out to see which floats your boat.

And even then, you have to be a bit careful about which apps you use: Using KDE apps, like konqueror, for example, can drag in great swathes of the kde infrastructure in order for it to run under a 'foreign' environment, so do 'before' and 'afters' on starting them up to get an idea.

Linux does by default cram as much into RAM as possible.That doesn't mean it wouldn't work with less RAM.

Get something configureable like a Debian netinstall or anything similar that doesn't install a lot of things by default and then just install what you need.

I did run Puppy on a laptop with 256 Mb RAM w/o harddrive and even there firefox (which is a recource hog) worked.
But I wouldn't go the Puppy or dsl route either.

There is nothing stopping you from installing only the same apps Puppy comes with with a different distro.

You also might want to stick to apps from one gui environment so you don't have gtk and qt loaded all the time.

You don't understand how it works, that's why.

Today, I'm going to write this on my site and put it in my sig so that everyone will understand.

The RAM is being used for the disk cache in order to SPEED UP THE SYSTEM. It is not draining resources. It could be a leak tho. If you would post the output of 'free', it would help.

Also, different distros require different minimum hardware, because some features require more resources to run. Even within a distro you can customize it to be much less resource hungry. However, most distros, especially popular ones come bloated by default.

This depends on how old the PC's in question are and what you want to do with it in the 3rd world. You could omit the X server and with it all GUI applications, stop a lot of services and be able to run it within 16 MB of RAM - chances are that no one will want to use it, not even in the 3rd world. Maybe even more in the 3rd world, as they really feel the need to catch up in terms of technology.

It's the same problem as with donating old PC's to schools: in the end all the kids show up with their new game CD's, just to find out that those old PC's (even W2k is already "ancient" to them) will not play these games. It's either the video card, video RAM, system RAM or hard disk space that is not sufficient enough. So you end up with disgruntled remarks and the need for up-to-date PC hardware.

Linux

I use Archlinux which installs with nothing other than the bare essentials to boot + package manager. adding the things you need are as simple as pacman -S packageA packageB packageC (deps are handled automatically) and my system boots with around 100mb of ram used. After having it on all day/night (kind of uncommon for me cause its a laptop) and with bout 10 tabs on firefox my ram is in the low 400's and the system is snappy (900 mhtz eee pc). No bloat for the win =). Ah and i'm using Openbox as my DE/WM

edit: why do things slow down for you when your ram usage goes up? i thought that unused memory was essentially just wasted memory and you woudlnt' experience slowdowns until you ran out and had to start using the HDD.

Here's how I see the use of ram memory.
And as previously mentioned, Debian gives you the option of installing a base minimal system, then you add what you want. It's not as flashy as other distros, but you can dress it up like the rest if you want, flashy comes with a price. I run Debian when I need a OS to work hard and fast with large tasks. If I'm in a relaxed mode, I like my Mandriva, mostly because I have nicer photos displayed on the multiple desktops in it. Both with KDE desktop. Here's how I install the rocket with a desktop (Debian).
I have 4GB of ram memory. With Compiz-fusion running in Debian with KDE and all the software I use on a regular basis installed, kinfocenter sees 3.8GB of ram, 3.23GB of it is free. But when running compiz-fusion, you only have one desktop photo displayed.

I disagree with the suggestions to use a lightweight desktop environment or wm like XFCE or IceWM or fluxbox, unless you're using a computer with less than 128megs of RAM.

One thing to understand about linux is that it doesn't swap out stuff out of RAM unless it really has to. During boot up, it will load up a lot of stuff and leave it in the RAM disk cache even though it doesn't really need it anymore. That RAM is considered "used" even though it can be reallocated at any time at a moment's notice. It's just that linux doesn't do it unless you really are running out of RAM.

I don't know how "bloated" Mandriva is, but I really can't imagine its all THAT much more bloated than Ubuntu (which doesn't have a reputation for leanness either). I can run Ubuntu out-of-box with its heavyweight GNOME desktop environment on a 128meg machine. With Debian (a distribution with a reputation for leanness), I can load up a full GNOME desktop environment on a 64meg machine (but trying to run the relatively bloated Firefox will be uber-sluggish).

For someone new to linux, I never recommend starting with a lightweight desktop environment. Full blown GNOME or KDE is easier to ease into, with their copious GUI tools and more mainstream support. If your computer has 128megs or more or RAM, it'll run either of them. It might not be the zippiest thing, but IMHO it's better to start with a slow desktop than one where you don't know how to do what you want to do.

Xfce is a full blown desktop environment, it is more of a middleweight than lightweight. It isn't in the same class as IceWM, or any of the *box window managers. Honestly, I prefer Xfce over Gnome, regardless of system resources, there is really nothing it can't do that Gnome can. It isn't that different from Gnome, it is just a little simpler, less uselss "features" to get in the way.

Just because Ubuntu can run in 128mb of RAM, doesn't mean it is going to be an enjoyable experience.

But the OP seems to have 1 gig or more... that seems to be fine. If his system becomes sluggish after a couple of programs are open, the ram usage is probably not the problem, and a lightweight desktop won't make much of a difference.

That's cuz you've never tried one.

No, actually I did use quite a lot of them for quite some time.
It does make a difference once the PC's resources would cringe under a standard gnome installation. But that doesn't seem to be the case with the OP.

I think this article may help the OP understand why Linux seems to use up a lot of memory. Unless the system starts swapping a lot, then I personally would not be worried. Firefox is always sluggish for me even on a system with 1GB ram, so sometimes I use Opera or Konqueor.