Speed starts normal then shoots down by 20mbps

Have Zen bought in any sort of throttling lately ? If not then any ideas what could be the issue ? I notice when I do a speed check my usual 60mbps speed now starts at that, but within seconds it is dropping down to 38mbps, it never used to do this. I first noticed it last night, around 5am, so I know it is not congestion. My IP Profile is still the same as before so that hasn't dropped.

I am on the 80mbps unlimited FTTC package. I use a wired connection.

Just wondered before I contact them if anyone might know the reason ? Thanks.

Happening to me too. Rebooting the router seemed to work when it happened a week or so ago, but it's started again. Speed dial on the speed test jumps to around 60 Mb/s then falls down to 30 or so. Upload speeds are about normal, at 18 Mb/s

Mine is the other way around. Starts low and builds up slowly to a max around 30-40% into the speedtest. Upload is fine.

Just an update on this, it's still ongoing. I went as far as to swap routers entirely, and I get the same pattern of behaviour, an initial jump to normalish speeds, then a slow decline to around 30 Mb/s where it levels off. Uploads are normal at 18 Mb/s.

I have contacted Zen support, so let's see what ensues.

Update 2
After a re-synchronisation, my speeds are back to normal.

Just one of those internet mysteries I suppose.

How interesting. My line is experiencing the same type of issue as you guys. Syncs at 60Mb and download starts at that and then gets throttled to 50% of the line speed.

I rebooted the modem but it didn't help...

I've contacted support. Hopefully they will find out what the issue is.

In reply to a post by RobWatts:

Update 2
After a re-synchronisation, my speeds are back to normal.

Just one of those internet mysteries I suppose.

Probably obtained a different routing, some routes on Zen are slower and have more latency than others.

Another one here ... seems to be a growing menace on the Zen side of things.

Had it early June, then improved and now back again .. despite resync.

Annoying is this is down to 30Mb from a 55 sync .... used to sync at full whack before crosstalk so 75 down to 30 hurts to say the least !

I spoke to Zen support. They say there have been a number of customers with very similar problems. My support representative is hopefully putting together a case that he can give to his network operations team to investigate.
I have a 60Mb sync too which goes down to 30Mb, after a second or so at the full 60Mb. I've tried reconnecting several times. Resyncing my circuit hasn't helped one little bit. My traceroute if it helps anyone...

1 192.168.178.1 (192.168.178.1) 0.370 ms 0.271 ms 0.254 ms
2 vt1.cor1.lond1.ptn.zen.net.uk (51.148.72.21) 7.778 ms 9.078 ms 9.778 ms
3 ae-12.cor1.leed1.ptn.zen.net.uk (51.148.73.22) 12.936 ms 12.920 ms 12.714 ms
4 ae-26.cor2.roch1.ptn.zen.net.uk (51.148.73.51) 15.909 ms 15.808 ms 16.068 ms
5 ae-25.cor1.roch1.ptn.zen.net.uk (51.148.73.49) 15.941 ms 15.939 ms 19.304 ms
6 xe-3-1-0.cr2.sp-roch.zen.net.uk (51.148.73.61) 15.006 ms 15.058 ms 15.245 ms
7 ae8-0.ar3.sp-roch.zen.net.uk (62.3.81.238) 14.990 ms 15.001 ms 14.802 ms
8 up1.1-pub.zen.net.uk (62.3.80.130) 15.165 ms 15.122 ms 15.224 ms
9 172.17.41.2 (172.17.41.2) 15.446 ms 15.534 ms 15.014 ms
10 web01.web.zen.net (212.23.8.83) 15.260 ms 15.139 ms 14.965 ms

OK I now have full speed again ... couple of router swaps no change .. back to orginal and full service.

Route is :

1 <1 ms <1 ms <1 ms fritz.box [192.168.0.1]
2 103 ms 99 ms 87 ms vt1.cor1.lond2.ptn.zen.net.uk [51.148.72.23]
3 92 ms 86 ms 83 ms ae-2.cor1.lond1.ptn.zen.net.uk [51.148.73.2]
4 79 ms 94 ms 94 ms ae-1.agg4.lond1.ptn.zen.net.uk [51.148.73.84]
5 125 ms 98 ms 95 ms vl-50.ae6.cr1.th-lon.zen.net.uk [51.148.73.57]
6 102 ms 95 ms 96 ms xe-2-0-0-172.dr1.lr-slo.zen.net.uk [62.3.80.102]
7 75 ms 92 ms 87 ms cache03.dns.zen.net.uk [212.23.6.100]