I use WeeChat as an IRC client and it runs on my Raspberry Pi. Because
  of that, it's rather slow.

  Found out that hiding the nicklist gives  a  huge  performance  boost.
  Either hide it completely or just hide it on crowded channels[1]:

    1   nicklist.conditions = "${nicklist} && (${buffer.full_name} != irc.freenode.#archlinux)"

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  1.
     https://weechat.org/files/doc/devel/weechat_user.en.html#bar_conditions