Desktops/Window Managers

Budgie

Cinnamon

Requirenments
CPU speed:
512MB
Memory:
1GHz
My Comments:
I would say a MINIMUM OF maybe in the 1.8GHz+ for the processor (guessing there) ... and at least 2GB of RAM for COMFORTABLE usage, myself

Gnomeshell/Gnome 3

Distros that Feature:
CPU speed:
768MB
Memory for Comfortable USE:
400MHz
My Comments:
There is NO WAY I can respectfully agree with this... My 2.2Ghz dualcore, 4GB Toshiba from 2009, would be an indicator OF THE MINIMUM I would even think of .. these specs have to be an UN-updated spec for Gnome2 but not Gnome3/Gnomeshell .. see "Mate" for the so called continuation of Gnome2, below

LXDE/LXQT

Distros that Feature:
CPU speed:
128MB
Memory:
266MHz
My Comments:
I am not 100% sure on these recommendations, though if there is one option listed for "lower end specs" that may be fine with specs like these... LXDE/LXQT (note to self: put in link to explain LXDE-vs-LXQT here) would be the option that works good on lower end hardware.

Mate

Updated DE that some 'consider' a continuation of 'Gnome 2' and it’s look and feel

Mate Homepage
Distros that Feature:
CPU speed:
512MB
Memory:
800MHz
My Comments:
I am not sure what I would say for "Comfortable" usage daily, though I have the Ubuntu Mate Pi2 version here, and while not perfect at times ... consider the cost of the Pi2 + accessories (for an example) ... it is REALLY not too bad

Plasma 5 (aka 'KDE 5')

Plasma 5 (aka 'KDE 5')
Distros that feature:
CPU speed:1GHz
Memory:615MB
My Comments:I am not sure if these are KDE4 or Plasma 5 specs listed above though I would say at LEAST 2GB of RAM and 1.7GHZ+ for the processor.

XFCE

Distros that feature:
CPU speed:
192 MB
Memory for Comfortable USE:
300Mhz My Comments:I'd say it may run at those specs above, though my thinking is at least 512MB of RAM to 768MB MINIMUM and maybe oh ... 1GHz for "regular" usage of what you'd probably want to do