Poor connection

I've recently switched to virgin media and from day 1 have not had a good connection. Speed tests always show good results yet connections can be really poor. The modem light has never been white ( I'm aware that the light can change from white to orange on an older modem but this is brand new. My security camera on the back of the house doesn't connect ( there was no problem with previous provider ) and I'm unable to get anything in the garage where I need the Internet.

Any help appreciated