Nagios 2.10 doing nothing for 5min after reload?



I just installed nagios 2.10 on our servers, and I have a “problem”: it seems like nagios is doing nothing for about 5min after a reload.
Here is a screenshot of what I’m trying to explain.

BTW, I’ve tried to play a little bit with the variable “max_service_check_spread”, but it doesn’t seem to improve a lot because when I’m trying it with a low value, I get huge latency before the problem I’m talking about is solved.

has any one the same problem ? how can I solve this ?

Thanks for your help

ps: (the 5min sleep mentionned in the title are with a max spread of 15min on 1400 services;
If I put 10min in max spread, I get something like 3.5min sleep.
If i get lower than 10min, I can lower the sleep time, but the latency increases …)