slow down

When I start BI my system starts responding very sluggishly after about 1h. After a few hours all HikVision and Dahua cameras freeze up (the time embedded by the cams is not updating anymore). Only a couple of cheap wireless cameras are still responding. When I go to the settings of a HikVision...

I know is better to have ip cameras connected wired, but I dont like the idea to put a large cable all around my house. I´m working on this right now. I have 1 WIFI Camera and the network works fine. But if I connect 2 WiFi cameras (just 2) my internet connection drop from 50Mb/s to 1Mb/s. I...