What causes Ruby memory bloat?
Here are some benchmarks on an 8-year-old, 4-core i7 running OSX Sierra. Parsing a 115Mb log file for lines containing a 15-character word (regex: \b\w{15}\b) we have:  LANG / TIME* / RAM

  JS (Node 11.11) / 8.4s / 100Mb
  Ruby 2.6 / 19.1s / 14.8Mb
  PHP 7.3 / 4.4s / 5.6Mb
  Python 3.7 / 24.7s / 4.2Mb
  Perl 5.26 / 14.0s / 1.0Mb

*These figures are for runtime, ie. with startup time deducted. Ruby's startup time (0.55s) is much longer than the other languages (Python:0.06s, Perl:0.02s, PHP:0.14s).Ruby's memory usage is 3.5 times that of Python for only a 30% speed gain. Perl uses 1/15 of the RAM used by Ruby and is 35% faster but it could be argued that Perl 5's lack of built-in OO accounts for some of this ..... until you look at PHP which has built-in OOP and uses 2/5 of the RAM used by Ruby whilst performing 3.2 times as fast.I love that Ruby is designed from programmer happiness but the shine starts to wear off when you look at its memory usage. Slow is bearable as it's only marginal but Ruby's memory usage is orders of magnitude higher it seems. Matz's goal of making Ruby 3 times faster is only half the battle, maybe even only a third. If an increase in speed comes at the expense of even greater memory use then Ruby will not survive.