I have a 2009 iMac (Intel Core 2 Duo, 4mb RAM) sitting here that needed even lighter. I found Bodhi 6.0 booted its full graphical desktop (Moksha, a fork of Enlightenment) in 250Mb of RAM. Not a typo. I was so impressed at how zippy it was I installed it on an old HP Pavilion G6 laptop (Core i3, 4mb RAM, SSD) and it positively flies.
K-9 FTW!