Dell Latitude D600
1GB RAM
80GB hard drive (I think...might be 60GB)

Widows XP wasn't working, so loaded CentOS 5 awhile back that is (as you can imagine) a dog on this underpowered laptop
Tried to upgrade to later CentOS, but hardware is apparently not compatible
(I run CentOS 7 on new production servers)
Based on research here, I'm thinking lubuntu -- thoughts?

Also old HP desktop.
1GB RAM
80GB hard drive.
Also running CentOS 5 -- it performs some better, but still pretty slow.
also lubuntu?

Thanks for any suggestions.

Yeah you can try Lubuntu.

http://lubuntu.net/

You can also give Anti-X a spin. It's designed for older pc's.-

http://antix.mepis.org/index.php?title=Main_Page

OR> run Puppy Linux Live and see if you like it.

1 members found this post helpful.

I'd say Anti-X or q4os for me. However that old you might have video issues.

Maybe try 'longshot' Zorin, which I and others had amazing success with (tho 'heavier')
Note DistroWatch.com search for 'Old Computers'. Is it this model?
Once/if you find a distro you like on it, It might be worth the $15 to upgrade to 2x1G ram (2x512M currently?)
The ol' D600 was one of the most common/popular laptops (32bit)

BunsenLabs, a community continuation of CrunchBang, should work fine on both of those laptops. BunsenLabs uses a combination of the Openbox window manager and the Tint2 panel to create a desktop environment. However, the development team is still working on the stable release of Helium, which is basically a customized Debian Stretch. If you don't want to wait for the official release, checkout this thread for details on installing a beta version of Helium.

Debian Linux minimal version with LXDE desktop would also be a good option.

My personal preference would be Debian with XFCE4, but in any case the big performance bottleneck will be the slow CPU (400Mhz Pentium M?)

I have a few computers that slow, but I don't use them for anything heavier than mp3 playing and XFCE4-terminals, sometimes VNC client for a faster computer. Web browsing is extremely limited.

That said, my slow computers also have much less RAM than 1GB.

The published specs show a Pentium M with 400 MHz FSB. If that's the case, you have the Banias version which does not show the PAE support flag: PAE is actually there, but distros that want it won't run because they think it isn't.

AntiX will definitely work straight away. Any distro should work if you add "forcepae" to the kernel parameters. On my Pentium-M Thinkpad, I use Salix.

PS the fact that you don't need PAE with only 1GM is irrelevant: if the kernel wants it, it insists on having it!

Certainly Debian will run out-of-box. I use the 686-pae release of Debian on plenty of computers without PAE and it just plain works. The kernel most definitely does NOT insist upon having it.

Yup. PROCESSOR, 80536, PENTIUM M DOTHAN, Pentium M Dothan, 1.8GHZ, 2 MEGB, 400FSB, PLASTIC GRID ARRAY, B1
2 DUAL IN-LINE MEMORY MODULE, 512, 333, 64X64, 8K, 200

Thanks to you all. I'll do some digging and trying (there's nothing needs to be preserved on either 'puter..I used the HP desktop to get familiar with CentOS 5 before building the production webserver. The laptop I just gave up on and bought an 8GB PC with a 500GB HDD desktop, then loaded CentOS 5 on the laptop.) Struggled for months to get the wifi working, then a solution just showed up in the repos...it runs well enough at the CLI, but the GUI is (maybe) even slower than Win XP ('twas a long time ago...)

Puppy Linux! I'm running Tahrpup 32bit on an old Compaq computer that has 500mb ram. and only 80gb harddrive. Puppy is one of the easiest and fastest Os that I've run so far.

1 members found this post helpful.

You're Welcome.

Let us know how things go and what distributions works for you on your machines.

Cheers:-

Oh! 1.8Ghz Pentium M! Sorry I read a bad reference (CNET). I actually have one very old laptop with a 400mhz Pentium M, so the bad reference didn't stick out to me as a red flag.

There's a world of performance difference between a 400mhz Pentium M and a 1.8Ghz Pentium M. That is actually not too bad for web browsing, watching video files, and general use. YouTube performance will be so-so, though, and you can forget about Netflix. I've got similar 1.8Ghz machines and it's utterly hopeless for Netflix.

Anyway, Debian with XFCE4 will run just fine on that laptop.