I've got some rather old hardware - Pentium Dual-Core E5400, 2.70GHz and 2 GB RAM (I'd get 2 more GB of RAM soon), and I want to get Ubuntu MATE LTS on it.
I currently have 14.04, and it works sluggishly at times, but doable. The bottleneck is RAM though.
But 14.04 is retired now - so would 18.04 or 16.04 LTS work here?
I ran UM 16.04 on a Core 2 Duo with 2.9 GHz and 4 GB RAM for several years just fine.
Currently I have the latest Linux Mint on that device, which is based on Ubuntu 18.04 and that also works well, so at least once you get the extra RAM you should be fine with either version.
That's a 64bit capable CPU. Very similar one of my test systems and 18.04 runs very well on it. That additional 2gb of RAM will make it work very nicely.
My advice would be to go with 16.04, unless you absolutely NEED something in 18+ (HiDPI support, basically).
18.04 is noticeably slower, and uses GTK3 which brought a ton of regressions, bugs, and lost functionality. Many of those problems HAVE since been worked around, but some haven't; some basically can't be; and even some of the major ones that have been haven't been backported to 18.04 - Caja crashing when you eject a USB drive is one that springs to mind.
I agree that the bottleneck is 2 GB RAM.
My advice would be to acquire and install as much RAM as you can (8 GB should do quite well) and then install UM 18.04.3 LTS. I have 2 laptops with slower CPUs that do very well running 18.04, one with 8 GB RAM and the other, 4 GB RAM.
Thanks for replies, everyone! Looks like 16.04 could do for the time being, and then I might try 18.04 when I get further RAM and/or better HW altogether, and when they (hopefully) sort out existing bugs...
Caja crashing when you eject a USB drive is one that springs to mind
...like this one. I get occasional Caja crashes on current setup as well, glad to see it might not be me doing something wrong.