Big drop in speed since last Monday.

Forums › Spark New Zealand (including Skinny and BigPipe) › Big drop in speed since last Monday.

weetbix43

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#215099 12-Jun-2017 15:56

Hi Guys.

Before I had this speed drop I have tried as much as I can. I tried a different router no change, I have had chorus out he says all looks fine but can't explain the drop in speed. I have changed filters I just don't know what else I can do?

Before the drop in speed downstream line was 30000 kbits
maximum downstream was approx 32-33 down kbits (both were close together)

downstream noise safety coefficient reported 8.9 - 9.1

line attenuation 47.2 or 47.8 so nothing changed there.

on speedtest I easily got 28 - 30 down

now I am lucky to get 20 - 21 such a big drop.

no matter what I do, resets etc nothing works.

here is a screenshot of what I get now

sbiddle

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#1798598 12-Jun-2017 16:12

Do you have a master filter?

Your speed looks fine for those stats. The drop was probably DLM adjusting your profile.

weetbix43

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#1798602 12-Jun-2017 16:16

Hi sbiddle. No master splitter. I just have the one jack.

With this DLM adjustment it can drop your speed back that much?

sbiddle

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#1798604 12-Jun-2017 16:18

weetbix43: Hi sbiddle. No master splitter. I just have the one jack.

With this DLM adjustment it can drop your speed back that much?

If it's detecting an unstable line, yes.

You don't do anything abnormal such as regularly rebooting your modem or turning it off do you?

Coil

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#1798606 12-Jun-2017 16:21

DLM may have made a change here.
If the HG you have is correct in saying Interleaving is off we can assume your are on DLM1 which is the best profile.
It may be due to a fault which is slowly emerging or just as simple as a neighbor got VDSL. (Noise floor has risen so it needs to compensate more)

Jase2985

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#1798608 12-Jun-2017 16:21

Sounds like this:

https://www.geekzone.co.nz/forums.asp?forumid=49&topicid=210455

Coil

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#1798609 12-Jun-2017 16:22

sbiddle:

weetbix43: Hi sbiddle. No master splitter. I just have the one jack.

With this DLM adjustment it can drop your speed back that much?

If it's detecting an unstable line, yes.

You don't do anything abnormal such as regularly rebooting your modem or turning it off do you?

System uptime is at 20 minutes so i suspect OP may have done a reboot.

@weetbix43 leave the modem alone completely. No reboots or resync's.
Monitor for 72 hours.

If it gets worse call up and log a fault :)

Lenovo

Shop now for Lenovo laptops and other devices (affiliate link).

weetbix43

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#1798623 12-Jun-2017 16:38

Since last Monday I have done quite a few reboots trying to get the speed to where it once was but I will leave it do to it's thing over the next 4 or 5 days and see where I am at then. I guess for now nothing much I can do but monitor.

Thanks everyone for chipping in it gives me a better insight on thing's.

:)

PS @ TimA you could be right there about a neighbour getting VDLS. I have noticed on wifi a different Modem showing up could be for vdls.

Coil

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#1798626 12-Jun-2017 16:42

weetbix43: Since last Monday I have done quite a few reboots trying to get the speed to where it once was but I will leave it do to it's thing over the next 4 or 5 days and see where I am at then. I guess for now nothing much I can do but monitor.

Thanks everyone for chipping in it gives me a better insight on thing's.

:)

PS @ TimA you could be right there about a neighbour getting VDLS. I have noticed on wifi a different Modem showing up could be for vdls.

Yeah chances are! Just leave her be for the next while. As they say, if it isnt broke dont fix it! (Slightly degraded in this case :P)

Even ADSL could do it. I once had 2 VDSL connections. Both were slightly modified by chorus but proves the point! If i had them up and running and resync'd one of them i'd lose DSL across the other due to the noise margin raising and the Signal to noise ratio dropping! We were running more voltage etc.

RunningMan

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#1798711 12-Jun-2017 17:41

weetbix43: [snip] Since last Monday I have done quite a few reboots trying to get the speed to where it once was

This will make the line appear to be very unstable, so it will pull you back to a more conservative profile. Just leave it alone.

sbiddle

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#1798913 12-Jun-2017 19:56

weetbix43: Since last Monday I have done quite a few reboots trying to get the speed to where it once was

This would have had the exact opposite effect.

smalltrader

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#1798952 12-Jun-2017 21:06

Weetbix43,

What you are seeing is ddDLM trying to fine tune your line for optimum performance. As other have said, just leave it alone and do not do frequent reboots as that will confuse ddDLM.

My personal experience is ddDLM will try to establish the upper limit and lower limit of stability vsperformance hence the big swing in sync speed. Since ddDLM went live on line in late April:

My down stream sync speed has changed from 52Mpbs -> 58 Mpbs - 62Mbps -> 49Mbps -> 48Mbps -> 47Mbps -> 56Mbps.
Up stream has changed from 10 Mbps -> 18 Mpbs - 16 Mbps - 22 Mbps

As you can see it is quite a wide swing and it it very tempting to reboot the modem to try to get back the old higher sync speed. However, don't do frequent reboot as ddDLM will do the job for you if your line can sustain a higher sync speed.