AX86U pro swapped for AX6000 now download sucks

[copywizard]

Ok so let me sketch the situation.

I had a AX86U pro for years and it worked fine using a fiber line 1Gb/1Gb (synchronous line).
When i downloaded large files from several different sources i mostly got steady download rates of 90/95MB a second so around 950Mbits which is fine.
But to future proof my network i bought a AX6000 this is because in the future i want a 2Gb/2Gb (synchronous line) and the AX6000 has 2.5Gb WAN and LAN ports and the AX86U pro only has one of those.
but now when i download the same files from the same websites i get max 4 or sometimes 20MB a second.
Speed tests always give me 950Mbits up and down and the network is as stable as it can be everything works fine except the download speed is abysmal after the swap.

So the question is how is this possible? and how could i fix this?

Some clarification:
Just to be sure this testing is ALL over cable no Wi-Fi is involved.
And both routers had the latest version of merlin installed.
The whole internal network consists of 2.5Gb switches and worked fine before i switched the routers.
The routers where/are both directly connected to the FTU so there is no "provider" modem between it.
Non of the wiring has changed.
For legal reasons i cannot disclose the downloaded files nor the location but i love retro games to just give you an idea.
I cannot swap back because i already reset my old router back to factory so the swap back would mean alot of work.

What i already tried:
I already played around with QoS without any luck.
I swapped cables and swapped from the 2.5Gb LAN port to the 1Gb LAN port without success.

 

[bennor]

How did you setup the AX6000 when you swapped it in? Did you manually configure it, or did you import the router.cfg from the RT-AX86U Pro?
If you reset the AX6000 to factory default and do a simple basic initial configuration, before configuring all the extra settings specific to your use case, do you experience the same slowdowns?
Have you tried the stock firmware on the AX6000 to see if you exhibit the same issue under stock?
Are you running any Asus-Merlin addon scripts?
Do you have a USB drive attached to the AX6000?

 

[degrub]

turn off QOS completely.
MTU ?
Something is different in your WAN port / provider config on the new router.
Which code base fork are you on ? 3004 or 3006 ? Same as before ?
Go back to stock firmware and factory reset after doing so.
do minimal config to get working and test each time after adding/changing settings.

did you accept any of the AiProtect stuff on the new router ?

 

[copywizard]

How did you setup the AX6000 when you swapped it in? Did you manually configure it, or did you import the router.cfg from the RT-AX86U Pro?
If you reset the AX6000 to factory default and do a simple basic initial configuration, before configuring all the extra settings specific to your use case, do you experience the same slowdowns?
Have you tried the stock firmware on the AX6000 to see if you exhibit the same issue under stock?
Are you running any Asus-Merlin addon scripts?
Do you have a USB drive attached to the AX6000?

Good questions I started from scratch with the ax6000 I thought about importing the config of the 86u but I didn't.
I,am running yazdhcp installed thru mtdm and this was also the case with my old 86u.
I have a raspberry pi that is powered by one of the two USB ports and a noctua fan in the second to cool down the router. But as mentioned this was also the case with the 86u.

turn off QOS completely.
MTU ?
Something is different in your WAN port / provider config on the new router.
Which code base fork are you on ? 3004 or 3006 ? Same as before ?
Go back to stock firmware and factory reset after doing so.
do minimal config to get working and test each time after adding/changing settings.

did you accept any of the AiProtect stuff on the new router ?

I have turned on QoS and also off also set file transfer as the main priority but you no avail.

The config was copied over from my old 86u. I,am on 3006.102.5_0 on both routers.

I have accepted the AI protection stuff

You both say start over and use the stock firmware I will do this as soon as possible because this means I have a lot of down time. So I need to find the right moment.

Thanks so far for the hints

 

[degrub]

nothing on the USB ports to start with until you finish step by step config change/testing. Get a plug in for the rPi and fan. You should not need a fan anyway if in conditioned space.

no scripts or anything extra until the base config is working correctly.

Are the packets from the sites you download from UDP or TCP/IP packets ?

The AI protection can definitely slow things down. Make sure it is turned off and revoked / never accepted. You have to do both if you have accepted it. You can always accept and enable later.

QOS should be on default settings e.g. off and no "priorities".

Are you running a VPN server on the router ?

step by step add/change then test is the only thing that can tell you what is causing the issue since we cannot see your config.

 

[bennor]

I have turned on QoS and also off also set file transfer as the main priority but you no avail.
I have accepted the AI protection stuff

Turn OFF the QoS and turn OFF the AiProtection.
Go to the Administration > Privacy page and Withdraw from the QoS and AiProtection/TrendMicro entries, if they are listed. Some will recommend selecting all the Withdraw buttons listed on the Privacy page.