When I first got FTTC, BT reckoned that this line would only do 9.9Mb which meant that Zen wouldn't offer FTTC. I'm not sure why, but there it is. In fact, every line on the cabinet was supposedly only able to get 9.9MB down 1Mb up, according to BT. Even the ones five metre from the cabinet. BT would not accept that this has to be wrong.
The line initally synched at 39.9Mb but after a few days dropped back to the mid 30s, where it has stayed more or less ever since, creeping up with firmware updates in the modem.
I was with ICUK, and the line performance seemed OK, but there were so many admin resets and NAS errors that I decided to switch to Zen a few weeks ago. BT had finally revised their line speed estimates to something a little less ludicrous (25.7 down) and Zen seem more relaxed about long lines anyway.
I had expected better reliability from Zen, but I hadn't really expected much better performance.
As this line has a SamKnows monitoring box on it, I do have a clear record of the performance before and after the switch. And my goodness you can see the difference!
Latency has gone from the mid 35's (but ever-varying) to a steady 15.6ms
Downstream Throughput has gone from 30Mb to 36Mb
Upstream Throughput has gone from 6.4Mb to 6.67Mb
Packet loss has gone from zigzagging between 0.35% and 1.7% to between 0.06% and 0%
Jitter has gone from around 5.5 to less than 0.5
This is the same hardware, the same phone line, and even the same synch as far as I know. The router had new username and password, but the modem wasn't restarted.
Why on earth didn't I switch a year ago?