Does anyone know of any decent tests done within the last year which measured how memory hungry the main browsers are?
There's an article about memory usage comparison of popular browsers dated March 4, 2010.
Another article, dated July 9, 2009, gives memory usage statistics in a table:
The best browser for each test is highlighted in green, and the worst is highlighted in red.
GHacks provides 2016's data on 32/64-bit browsers memory consumption:
The winner after opening 10 tabs is Pale Moon 32-bit.