Slow Network devices after install of Box!

I have used two different Box units thinking maybe one was bad, the answer is no. Both boxes slowed my network down to a snails pace. At first I had DSL and was told download and upload from provider not enough. Changed providers and more than meet the required bandwidth they told me I needed. No change in network behavior and totally followed Box manufacture configurations, companion to router, disabling DHCP. Again, slowed to a snails pace and will not recognize all devices on network. Has been over 6 months of trying with no resolution that I can use the Box. Still waiting on help!!