I do not know how calibre download web site news, but maybe the news collecting could be "faster"? Please note that this is not a big issue for me - I am just puzzled about the cpus usage:
* Embed the following Mozilla plug-ins/add-ons (useable in Firefox, Thunderbird and Eudora) in the embedded calibre web browser?:
** NoScript:
https://addons.mozilla.org/en-US/firefox/addon/722/
** Adblock Plus:
https://addons.mozilla.org/en-US/firefox/addon/1865/
* Maybe running more news source gatherings in parallel