Download Speeds limited below upload speeds

Hi,
I installed OpenWRT(22.03.5 r20134-5f15225c1e) on a newly(second hand) acquired ASUS RT-AC57U V1. I have a coax router from my ISP(Comhem/Tele2) that I've been able to set in bridge mode and my Open WRT router gets a an IP via DHCP from my ISP and i can browse the web. All good.

Now for the issue:
When i run a speed test i only get ~20Mbit/s down and i get the full 50Mbit/s uppload while my ISP service is a 600D/50U line. I tried plugging the same cable that's in my WAN port directly to my PC and i get the full 600/50. I've done some troubleshooting from what I've found on the forums. So first the linkspeed between my coax router to my Open WRT router. When i run ethtool i get the following for wan and lan4 which my PC is on:

Settings for wan:
        Supported ports: [ TP    MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised pause frame use: Symmetric Receive-only
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                             100baseT/Half 100baseT/Full
        Link partner advertised pause frame use: Symmetric Receive-only
        Link partner advertised auto-negotiation: Yes
        Link partner advertised FEC modes: Not reported
        Speed: 100Mb/s
        Duplex: Full
        Auto-negotiation: on
        master-slave cfg: preferred master
        master-slave status: master
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: external
        MDI-X: Unknown
        Supports Wake-on: d
        Wake-on: d
        Link detected: yes

Settings for lan4:
        Supported ports: [ TP    MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised pause frame use: Symmetric Receive-only
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                             100baseT/Half 100baseT/Full
        Link partner advertised pause frame use: No
        Link partner advertised auto-negotiation: Yes
        Link partner advertised FEC modes: Not reported
        Speed: 100Mb/s
        Duplex: Full
        Auto-negotiation: on
        master-slave cfg: preferred master
        master-slave status: master
        Port: Twisted Pair
        PHYAD: 4
        Transceiver: external
        MDI-X: Unknown
        Supports Wake-on: d
        Wake-on: d
        Link detected: yes

It's weird that i get 100Mbps only while if i take the same cable directly to my PC i get a Gigabit connection. But 100Mbps is still quite a bit larger than the 20Mbps that i get when doing my BW test so i decided not to dig to deep into this yet.
The cable from my coax router to the Wan port is a 10m Cat 6 cable. Cable to my PC is 1m Cat6 cable.

I've also switched of all IPv6 setting as i read on some other posts.

I have tried using Software Flow Offloading only and in combination with Hardware Flow Offloading. These dose not change anything. And my CPU does not seem limited in this case.
Htop image while doing speed test resulting in 20D/50U:

In my firewall I've disabled SYN-flood protection(Read that migh cause issues in another thread). And also disabled NAT rules relating to IPv6.

I feel like I'm out of options at this point. Does anyone have an idea of what might be limiting my download speeds or what to check for? Any help would be greatly appreciated.

Okay so after writing this previous post I decided to look into why I only negotiate 100Mbps. Testing the cable with my PC as previously mentioned only left the “new” router to be checked. So I did a sanity check and looked at the physical port and to my despair this is what I found:

The image might not be super clear but some of the pins were bent in and did therefore not make contact.

I pulled out all cables and bent back the pins using a sewing needle. Plugged everything back in and now I get gigabit link and speedtest shows 600/50. Works like a dream.

I guess the previous owner must have had som bad cables that pushed these pins to be bottom. 4/5 ports had the same issue. That’s another weekend wasted on fixing stupid shit. On to the next one.

1 Like

Not sure if matters
but
When I ran ethtool wan command on MT7621AT router,
Unlike yours
The Link partner advertised link modes: also displayed the following:
1000baseT/Half 1000baseT/Full
Which yours is not displayed?

EDIT: Since it's resolved, disregard. :slight_smile:

Yhe, see my second post. It now does that for me too.