Parsing 355 files, 4524Kb (ripped from python.org)

lxml = lxml.html
bs = BeautifulSoup
html5_cet = html5 parser with cElementTree model
html5_et = html5 parser with ElementTree model
html5_lxml = html5 parser with lxml.html model
html5_minidom = html5 parser with minidom model
html5_simple = html5 parser with internal simple_tree model
lxml_bs = BeautifulSoup parser with lxml model
htmlparser = HTMLParser, with no parser actions, document string is its own model

python tester.py --no-gc

lxml           :   0.5156 sec ( 100% of lxml)
bs             :  10.3816 sec (2013% of lxml)
html5_cet      :  29.5829 sec (5737% of lxml)
html5_et       :  30.2433 sec (5865% of lxml)
html5_lxml     :  31.7533 sec (6158% of lxml)
html5_minidom  :  34.2963 sec (6651% of lxml)
html5_simple   :  28.7421 sec (5574% of lxml)
lxml_bs        :  12.2269 sec (2371% of lxml)
htmlparser     :   3.0968 sec ( 600% of lxml)


python tester.py --no-gc --serialize

lxml           :  0.2704 sec ( 100% of lxml)
bs             :  1.8265 sec ( 675% of lxml)
html5_cet      :  1.5960 sec ( 590% of lxml)
html5_et       :  1.7677 sec ( 653% of lxml)
html5_lxml     :  0.2755 sec ( 101% of lxml)
html5_minidom  :  3.4696 sec (1283% of lxml)
html5_simple   :  1.4929 sec ( 552% of lxml)
lxml_bs        :  0.2834 sec ( 104% of lxml)


VSZ/RSS increase:
lxml:            1168  /    120
bs:             82508  /  82176
html5_cet:      54620  /  54756
html5_et:       64688  /  64960
html5_lxml:     49076  /  49124
html5_minidom: 194304  / 192928
html5_simple:   98608  /  98004
lxml_bs:       104920  / 104852
htmlparser:      5412  /   4456

Note: htmlparser keeps all the strings of the documents in memory.