We've been with Infinity for quite a while now and i've been quite annoyed. We've had a problem where the internet disconnects for around 20 seconds every 10-30 minutes or so. We had quite a lot of trouble trying to get ahold of someone to help us fix this, and when BT actually decided to send an Engineer out he said everything was fine, when it's not.
We think we've found the problem but we have no way to resolve it, so i'll say it as simple as i can.
My PC is connected by a brand new 20M CAT5e ethernet cable to the HomeHub4. Yeas, brand new because we thought the wire was the problem, when it's not because we get the exact same problem as before. In the house we then have my PlayStation 3 and my parents laptop which are both wireless. Then very minor things coonected wirelessly like phones and a tablet. Whenever the internet drops everything will be disconnected from the internet for about 30 seconds before we can actually get back on, then we'll reconnect and the whole process will repeat.
However, when the engineer was here he gave us some tips, one of these was to rule out the different connections that might be causing this. I then disconnected my PC from the HomeHub4 by unplugging the cable to the hub and the internet was running perfectly smooth, no drops, no speed issues, nothing. Obviously the simple soloution would be to try another ethernet cable, which leads us to where we are now. Everything is exactly the same with the new cable and like before, the internet will be fine if i unplug the cable to my PC, however my PC is not capable of a wireless connection so you can see the problem here.
TL;DR - My infinity connection cuts out constantly when i have my PC plugged into the humehub4 directly but when i unplug it it's fine. Help please.
Check that your Network Card drivers are up to date. Use the card manufacturers web site not Windows which can be out of date.
EDIT: Have you tried connecting one of your laptops to the homehub by the Ethernet cable, making sure you turn of the laptops wireless, to see what happens?
If everything is OK then it would pint to the problem being with your PC and not the Ethernet cable or homehub.
I had a similar problem a few years ago that when I turned on my spare PC I'd loose the internet totally within a few minutes.
It turned out to be a virus/malware on that particular PC that I couldn't remove so had to reinstall Windows.