slow loading and refreshing-loop – problem

hallo enfold support

enfold site loads really slow,
it started to refresh every second, so i had to deactivate refresh and cache plugin

(the site i build is still on a subdomain. it´s planed to move it on the main-domain when everything is fixed)

already
– optimized pictures with photoshop
– use compression plugin optimize
– installed plugins for picture optimization, cashing an refreshing
but nothing changed

what can i do for a faster site without this refreshing problem?

thanks for your help,
katrin