Would you expect that from a bog-standard FTP download from my ftp account as well though? I presume it's not as full-on as a speed test which yes, I can see would be trying to push it to its limits.

And the tracert yesterday, there wasn't anything else going on on our connection at the time I saw the high pings, which is more worrying.

In reply to a post by Orddu:

Would you expect that from a bog-standard FTP download from my ftp account as well though? I presume it's not as full-on as a speed test which yes, I can see would be trying to push it to its limits.

In theory your FTP account can fill your line as well - but its possible your FTP provider limits the data rate, either per connection, or per IP address. This allows them to serve more people.

And the tracert yesterday, there wasn't anything else going on on our connection at the time I saw the high pings, which is more worrying.

It could also be that the routers don't bother to reply to your ICMP packets (from the traceroute) because they're busy doing real work.

In reply to a post by Orddu:

Alas not, we've tried at all hours, morning, midday, evening, middle of the night even. Always around the same mark.

Zen's service details on their site swear blind they don't cap speeds or traffic shape in any way.

Don't know what to say to them next, really.

That is correct zen do not cap at all

I think our traffic is not so much shaped as mutated!

The tracert didn't have any which didn't respond, only ones which normally give ~23ms and suddenly started giving ~200ms responses, when our connection was otherwise inactive.

You should expect high latency and packet loss if you saturate the connection.

OK, BT have now looked at it and confirmed that we sync at 36 meg as far as they're concerned.

Having tested all (*) the kit in the house, have passed it firmly back to Zen as a potential routing issue.

(*) But.

The only avenue we haven't explored is this potenial underrated PSU that you mentioned. The neighbours have had 5 new modems so far (I think the dog is eating them) but still have a black PSU - argh.

Networking I'm happy with, electrics less-so. Could you possibly point me towards a suitable higher-rated PSU I could buy and try out, please? If there's no change, pfft we tried. But it's the only thing we haven't had a go at and I like to be thorough. Plus we'd like to go to 80meg when it's available, but if it's overloaded at 40 then 80 ain't gonna help.

Ideally, "go into Maplin and ask for..." or a link to a mail-order site would be lovely

Thank you very much in advance!

I would say forget the PSU, I don't see how it can be relevant if it was working perfectly well with the old modem. Assurance after assurance has been given that the PSU is adequate for the new modems.

Well, other than a small outlay it can't actually hurt, and it is the only piece of kit left in the equation. I'm willing to give it a try for the sake of completeness if nothing else. Cos if I find out later it was that, I'm going to feel like a right nana!

Try a multithreaded download. A large DVD ISO of Linux on bittorrent, for example.

So your VDSL2 modem does work okay on a friend's line.. can you now borrow your friend's modem and try it on your line?

And just to satisfy yourself that the PSU is not the cause, maybe try your friend's PSU with your modem..

Who is telling you that your line is sync'ing at 36Mbps? BT but not Zen?

Since the Huawei, while locked, operates as a 'black box', you can't verify the sync speed yourself.

Can you source an unlocked modem temporarily?

cheers, a