User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:49.0) Gecko/20100101 Firefox/49.0 Build ID: 20160922113459 Steps to reproduce: I tried to open the following PDF documents: http://fondation.cetim.fr/pages/projets/fondationCetim_RecuperationEnergieVibrationsAmbiantes.pdf http://www.apur.org/sites/default/files/documents/incidences_evolution_loi_ALUR_bati_parisien.pdf Actual results: Firefox got stuck for several minutes, and this caused every opened tab to freeze too... Since the whole browser was now useless, my patience ran out and I killed the Firefox process. Ironically, the very same link, on the very same machine, at the very same moment was handled perfectly by Google Chrome. Each time, I got my PDF file in less than 5 seconds. Expected results: Firefox should be designed with any kind of machine configuration (mine is "old": a 2011 Dell high-end laptop) and any kind of files (a 50 MB PDF file is not large by current standards) in mind... My two cents (I apologize, they are not optimistic): since the switch to the new multi-threaded software architecture, I encounter a lot of usability problems like this. And each time Google Chrome delivers a far better result... This is sad: I need good tools to work with, and Firefox is less and less relevant to my work. Thanks in advance for your help!
I can reproduce the super slow if e10s mode. And big spinner is spinning for long period when I open other tabs while the pdf is loading. If disable e10s, it is faster as same as Chrome. And I can open other tabs properly while the pdf is loading. https://hg.mozilla.org/mozilla-central/rev/99a239e1866a57f987b08dad796528e4ea30e622 Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0 ID:20161020030211
Mass wontfix for bugs affecting firefox 52.
Can you still reproduce the issue? Both PDF's seem pretty snappy for me.
Dear Brendan, thanks for your feedback. I confirm that the issue is no longer showing up: the bug seems to have been caught in the meantime... I suggest that we close this report.