I am currently seeing very slow loading of the host overview pages which I think is due to loading data for the Runtime and Resources graphs.
I do have a large amount of reports for 7 days, for example over 9000 for a host and it takes about 10 seconds to render the page.
I've dropped the puppet agent poll period from 60 seconds to 300 seconds now to reduce the number of report updates.
However it would be better if the graphs did not block the page load or we could disable the graphs in some way, even setting the default view to 1 day not 7 would help.