Hi i am using piwik on my raspberypi-2 and it is really slow.
Would be nice if you can get some minimal Hardware Requirements in your Doc.
BTW, really thx for these awesome analytics tool.
The hardware requirements really depend on the use case and the number of visitors.
But if you can live with slightly delayed reports, then you can speed piwik up by disabling report generation in the browser and setting up a cronjob.
We've published new recommendations on minimum recommended server specs, please see: https://matomo.org/docs/requirements/#tracking-100000-pageviews-per-month-or-less
here is what it looks like now: