Sure Zentyal can be sometimes a bit slow at least for what concerns GUI
- It definitely has not been designed to run on small CPU (like Atom)
- Having added graphic user interface on server itself whoich makes user feel that this is the right way to manage Zentyal is even worst on such small platform.
- Because of some design choices, whatever you CPU, some steps are slow (like connecting to GUI first time or accessing dashboard depending on widgets...
However:
- aside admin GUI aspects, while running, Zentyal is not slow (although, again, not design for small platform)
even if it consumes more resources than equivalent platform (in term of feature) based on same packages without the Zentyal stuff around (*)
- significant progresses have been made already
- there is room for improvement
I'm sure Zentyal team listen and makes effort in this direction
(*) before running Zentyal, I installed almost identical platform on FitPC almost without any problem: FW, mail (postifx, dovecot, amavis), squid + filter... but went for light HTTP server for webmail and didn't add any admin interface