Odd speed issue

[#1]

Here's an interesting one...

FTTP 900, using all the original Plusnet supplied equipment. The Plusnet branded router and the Openreach supplied ONT.

Download speeds are down to 6-100mbit depending on what time of day I hit the button (upload is always full speed) - this is when using Speedtest.net and the Fast.com sites, plus general HTTP downloads. However, the BT wholesale speed test site comes back at full speed 850mbit ish, and I do see full speeds on the other speed test sites when connected to a VPN (Nord).

Plusnet support have also confirmed that I'm on the right line/speed profile. So I don't get it.

An Openreach engineer has been out, and light levels are in the green. So far, I'm stuck between Plusnet and Openreach trying to work out what's going on. So far, I suspect nobody has found the fault and we're left sat here struggling to work from home. Not just because of the intermittent speed, it's also dropping connection from time to time. 

Any thoughts on what this could be?

Ta v.much!

[#2]

it's also dropping connection from time to time. 

@ColinBe now that's very odd for a Full fibre connection!

Is it just a wifi drop or is the router losing the PPPoE connection ?

If you're not sure then check the router event log

[#3]

On closer inspection. That's a red herring. Put the "dropping connection from time to time" to one side. It's the higher latency causing sites to load much, much slower. Still don't understand the speed issues though...

Speedtest.net

Fast.com

BT Wholesale

Waveform

General browsing is sluggish. But, like I say, when on a VPN, full speeds for all Speedtest sites, and browsing is lightning.

[#4]

General browsing is sluggish. But, like I say, when on a VPN, full speeds for all Speedtest sites, and browsing is lightning.

@ColinBe that would point more towards a DNS problem, you will be using different DNS servers when on a VPN.

Are you using the default (Plusnet) DNS servers ? and do you have SafeGuard enabled ?

In terms of raw speed testing , the most consistent at higher speeds is Ookla ( speedtest.net ) , particularly the cli version https://www.speedtest.net/apps/cli as it eliminates any browser effects

[#5]

DNS - Google and Cloudflare.

SafeGuard is off.

Thanks

[#6]

I was having same issue until I changed to manual IP's on my pc vs DCHP. On DCHP I got 340 down on both single threaded and same on mutiple downloads via thinkbroad bands now I get 520+ on multi threaded speed tests

8.8.8.8
208.67.222.222

[#7]

For those who use a Hub Two it is possible to define your preferred choice of DNS

From the home page navigate >Advanced Settings >My network > IP4v configuration >DNS Servers 

Change Auto from Yes to No, then you can add your choice for Primary and Secondary hosts. 

HTH

[#8]

For those using a Hub2 it is worth considering that leaving it in default settings makes the Hub 2 the de-facto DNS resolver for devices using DHCP from the Hub2.

Changing the settings (as indicated by Dan_the_Van) propagates the DNS servers via DHCP to client devices using the Hub2 DHCP server.

DHCP on the Hub2 is (IMO) a bit weird.