Sometimes (quite often) a page on the Drupal.org site continually loads (i.e. Chrome shows it’s still loading as it shows its page spinner for that tab).
It doesn’t always happen, however it takes up about 70% CPU on a reasonably high end machine when it does. Once the offending tabs are killed Chrome goes down to < 4% CPU.
Example forum post that did it (although it won’t consistently do it)
Chrome Version 56.0.2924.87 (64-bit).
Let me know if you want me to debug this further. Always happy to help if I can 🙂
Note the problem doesn’t seem to occur on other websites.