I have been having a few issues where at times I am having to reboot my hub 4 due to web pages not loading properly or because my upload and download speeds are slow. Rebooting does seem to fix the issue for a while. I also had some T3 Timeouts on all channels but disappeared when I rebooted the Hub
For a bit more evidence set up a Broadband Quality Monitor (BQM) at thinkbroadband.com - this will give you an insight into what is happening with the signal at the Hub, it will take a few hours to get any kind of trend showing.
Post a link to your BQM on here.
Instructions for posting BQM Link
Under your BQM graph are two links in red.
Click the lower link (Share Live Graph) then click generate.
Copy the text in the Direct Link box, beware, there may be more text than you can see.
On here click the Link icon (2 link chain)
In the URL box paste the link you copied and then click OK
Just a update my speed as dropped and I'm only getting 10Mb upload speeds when I usually get around 50Mb. My download speed as cut in half as well. Spoke to Virgin Media on the phone but didn't find them very helpful.
Low S/N ratio on some of your low frequency downstream channels The 8dB variation in downstream signal levels from low frequency to high frequency channels Upstream signal levels too high (the modem is having to shout to be heard) Upstream modulation should be 64QAM not 8QAM - probably due to poor S/N ratio on upstream.