5GHz Low performance on TP-Link Archer C6 V2

Morpheus0 · August 31, 2020, 10:26pm

Hello Experts,

I am not an expert in OpenWRT here so I need your help finding out why I am getting half of what I used to get of download/upload speed using my stock firmware. I installed OpenWRT on my TP-Link Archer C6 V2 and tried multiple changes on the Wireless configuration including but not limited to:

Changing channels
Modifying VHT to 80
Changing country and TX power
Adding options like bursting, turbo, compression and enabling ff

Basically, my total bandwidth as per speed tests is ~450Mbps on my laptop and mobile phones (IPhone and Android). When I installed OpenWRT the maximum speed I got was almost 220Mbps.

Please note that no matter where I place the clients (near or far) I still don't get the actual speed

Latest Iperf results:

C:\Users\masahawn\Downloads\iperf-3.1.3-win64\iperf-3.1.3-win64>iperf3.exe -c 192.168.2.1
Connecting to host 192.168.2.1, port 5201
[  4] local 192.168.2.190 port 64469 connected to 192.168.2.1 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  15.9 MBytes   133 Mbits/sec
[  4]   1.00-2.00   sec  20.0 MBytes   168 Mbits/sec
[  4]   2.00-3.00   sec  19.6 MBytes   165 Mbits/sec
[  4]   3.00-4.00   sec  18.8 MBytes   157 Mbits/sec
[  4]   4.00-5.00   sec  18.2 MBytes   153 Mbits/sec
[  4]   5.00-6.00   sec  14.8 MBytes   124 Mbits/sec
[  4]   6.00-7.00   sec  15.8 MBytes   132 Mbits/sec
[  4]   7.00-8.00   sec  19.2 MBytes   162 Mbits/sec
[  4]   8.00-9.00   sec  16.2 MBytes   136 Mbits/sec
[  4]   9.00-10.00  sec  18.5 MBytes   155 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec   177 MBytes   148 Mbits/sec                  sender
[  4]   0.00-10.00  sec   177 MBytes   148 Mbits/sec                  receiver

iperf Done.

My router configuration:

root@OpenWrt:/etc# iwinfo
wlan0     ESSID: "xxxxxx"
          Access Point: D8:0D:17:6B:4B:36
          Mode: Master  Channel: 36 (5.180 GHz)
          Tx-Power: 23 dBm  Link Quality: 34/70
          Signal: -76 dBm  Noise: -106 dBm
          Bit Rate: 243.8 MBit/s
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11nac
          Hardware: 168C:0056 0000:0000 [Qualcomm Atheros QCA9886]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy0

wlan1     ESSID: "xxxxxx"
          Access Point: D8:0D:17:6B:4B:37
          Mode: Master  Channel: 11 (2.462 GHz)
          Tx-Power: 22 dBm  Link Quality: 36/70
          Signal: -74 dBm  Noise: -95 dBm
          Bit Rate: 36.4 MBit/s
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11bgn
          Hardware: unknown [Generic MAC80211]
          TX power offset: unknown
          Frequency offset: unknown
          Supports VAPs: yes  PHY name: phy1

root@OpenWrt:/etc# cat /etc/os-release
NAME="OpenWrt"
VERSION="19.07.3"
ID="openwrt"
ID_LIKE="lede openwrt"
PRETTY_NAME="OpenWrt 19.07.3"
VERSION_ID="19.07.3"
HOME_URL="https://openwrt.org/"
BUG_URL="https://bugs.openwrt.org/"
SUPPORT_URL="https://forum.openwrt.org/"
BUILD_ID="r11063-85e04e9f46"
OPENWRT_BOARD="ath79/generic"
OPENWRT_ARCH="mips_24kc"
OPENWRT_TAINTS=""
OPENWRT_DEVICE_MANUFACTURER="OpenWrt"
OPENWRT_DEVICE_MANUFACTURER_URL="https://openwrt.org/"
OPENWRT_DEVICE_PRODUCT="Generic"
OPENWRT_DEVICE_REVISION="v0"
OPENWRT_RELEASE="OpenWrt 19.07.3 r11063-85e04e9f46"



root@OpenWrt:/etc# iw list
Wiphy phy1
        max # scan SSIDs: 4
        max scan IEs length: 2257 bytes
        max # sched scan SSIDs: 0
        max # match sets: 0
        max # scan plans: 1
        max scan plan interval: -1
        max scan plan iterations: 0
        Retry short limit: 7
        Retry long limit: 4
        Coverage class: 0 (up to 0m)
        Device supports AP-side u-APSD.
        Device supports T-DLS.
        Available Antennas: TX 0x7 RX 0x7
        Configured Antennas: TX 0x7 RX 0x7
        Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * AP/VLAN
                 * monitor
                 * mesh point
                 * P2P-client
                 * P2P-GO
                 * outside context of a BSS
        Band 1:
                Capabilities: 0x11ee
                        HT20/HT40
                        SM Power Save disabled
                        RX HT20 SGI
                        RX HT40 SGI
                        TX STBC
                        RX STBC 1-stream
                        Max AMSDU length: 3839 bytes
                        DSSS/CCK HT40
                Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
                Minimum RX AMPDU time spacing: 8 usec (0x06)
                HT TX/RX MCS rate indexes supported: 0-23
                Frequencies:
                        * 2412 MHz [1] (22.0 dBm)
                        * 2417 MHz [2] (22.0 dBm)
                        * 2422 MHz [3] (22.0 dBm)
                        * 2427 MHz [4] (22.0 dBm)
                        * 2432 MHz [5] (22.0 dBm)
                        * 2437 MHz [6] (22.0 dBm)
                        * 2442 MHz [7] (22.0 dBm)
                        * 2447 MHz [8] (22.0 dBm)
                        * 2452 MHz [9] (22.0 dBm)
                        * 2457 MHz [10] (22.0 dBm)
                        * 2462 MHz [11] (22.0 dBm)
                        * 2467 MHz [12] (disabled)
                        * 2472 MHz [13] (disabled)
                        * 2484 MHz [14] (disabled)
        valid interface combinations:
                 * #{ managed } <= 2048, #{ AP, mesh point } <= 8, #{ P2P-client, P2P-GO } <= 1, #{ IBSS } <= 1,
                   total <= 2048, #channels <= 1, STA/AP BI must match, radar detect widths: { 20 MHz (no HT), 20 MHz, 40 MHz }

        HT Capability overrides:
                 * MCS: ff ff ff ff ff ff ff ff ff ff
                 * maximum A-MSDU length
                 * supported channel width
                 * short GI for 40 MHz
                 * max A-MPDU length exponent
                 * min MPDU start spacing
        Supported extended features:
                * [ RRM ]: RRM
                * [ CQM_RSSI_LIST ]: multiple CQM_RSSI_THOLD records
                * [ CONTROL_PORT_OVER_NL80211 ]: control port over nl80211
                * [ TXQS ]: FQ-CoDel-enabled intermediate TXQs
Wiphy phy0
        max # scan SSIDs: 16
        max scan IEs length: 199 bytes
        max # sched scan SSIDs: 0
        max # match sets: 0
        max # scan plans: 1
        max scan plan interval: -1
        max scan plan iterations: 0
        Retry short limit: 7
        Retry long limit: 4
        Coverage class: 0 (up to 0m)
        Device supports AP-side u-APSD.
        Device supports T-DLS.
        Available Antennas: TX 0x3 RX 0x3
        Configured Antennas: TX 0x3 RX 0x3
        Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * AP/VLAN
                 * monitor
                 * mesh point
                 * P2P-client
                 * P2P-GO
                 * P2P-device
        Band 2:
                Capabilities: 0x19ef
                        RX LDPC
                        HT20/HT40
                        SM Power Save disabled
                        RX HT20 SGI
                        RX HT40 SGI
                        TX STBC
                        RX STBC 1-stream
                        Max AMSDU length: 7935 bytes
                        DSSS/CCK HT40
                Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
                Minimum RX AMPDU time spacing: 8 usec (0x06)
                HT TX/RX MCS rate indexes supported: 0-15
                VHT Capabilities (0x339979b2):
                        Max MPDU length: 11454
                        Supported Channel Width: neither 160 nor 80+80
                        RX LDPC
                        short GI (80 MHz)
                        TX STBC
                        SU Beamformer
                        SU Beamformee
                        MU Beamformer
                        MU Beamformee
                        RX antenna pattern consistency
                        TX antenna pattern consistency
                VHT RX MCS set:
                        1 streams: MCS 0-9
                        2 streams: MCS 0-9
                        3 streams: not supported
                        4 streams: not supported
                        5 streams: not supported
                        6 streams: not supported
                        7 streams: not supported
                        8 streams: not supported
                VHT RX highest supported: 0 Mbps
                VHT TX MCS set:
                        1 streams: MCS 0-9
                        2 streams: MCS 0-9
                        3 streams: not supported
                        4 streams: not supported
                        5 streams: not supported
                        6 streams: not supported
                        7 streams: not supported
                        8 streams: not supported
                VHT TX highest supported: 0 Mbps
                Frequencies:
                        * 5180 MHz [36] (23.0 dBm)
                        * 5200 MHz [40] (23.0 dBm)
                        * 5220 MHz [44] (23.0 dBm)
                        * 5240 MHz [48] (23.0 dBm)
                        * 5260 MHz [52] (23.0 dBm) (radar detection)
                        * 5280 MHz [56] (23.0 dBm) (radar detection)
                        * 5300 MHz [60] (23.0 dBm) (radar detection)
                        * 5320 MHz [64] (23.0 dBm) (radar detection)
                        * 5500 MHz [100] (23.0 dBm) (radar detection)
                        * 5520 MHz [104] (23.0 dBm) (radar detection)
                        * 5540 MHz [108] (23.0 dBm) (radar detection)
                        * 5560 MHz [112] (23.0 dBm) (radar detection)
                        * 5580 MHz [116] (23.0 dBm) (radar detection)
                        * 5600 MHz [120] (23.0 dBm) (radar detection)
                        * 5620 MHz [124] (23.0 dBm) (radar detection)
                        * 5640 MHz [128] (23.0 dBm) (radar detection)
                        * 5660 MHz [132] (23.0 dBm) (radar detection)
                        * 5680 MHz [136] (23.0 dBm) (radar detection)
                        * 5700 MHz [140] (23.0 dBm) (radar detection)
                        * 5720 MHz [144] (23.0 dBm) (radar detection)
                        * 5745 MHz [149] (30.0 dBm)
                        * 5765 MHz [153] (30.0 dBm)
                        * 5785 MHz [157] (30.0 dBm)
                        * 5805 MHz [161] (30.0 dBm)
                        * 5825 MHz [165] (30.0 dBm)
                        * 5845 MHz [169] (disabled)
                        * 5865 MHz [173] (disabled)
        valid interface combinations:
                 * #{ managed } <= 16, #{ AP, mesh point } <= 16, #{ IBSS } <= 1,
                   total <= 16, #channels <= 1, STA/AP BI must match, radar detect widths: { 20 MHz (no HT), 20 MHz, 40 MHz, 80 MHz, 80+80 MHz, 160 MHz }

        HT Capability overrides:
                 * MCS: ff ff ff ff ff ff ff ff ff ff
                 * maximum A-MSDU length
                 * supported channel width
                 * short GI for 40 MHz
                 * max A-MPDU length exponent
                 * min MPDU start spacing
        Supported extended features:
                * [ VHT_IBSS ]: VHT-IBSS
                * [ RRM ]: RRM
                * [ SET_SCAN_DWELL ]: scan dwell setting
                * [ CQM_RSSI_LIST ]: multiple CQM_RSSI_THOLD records
                * [ CONTROL_PORT_OVER_NL80211 ]: control port over nl80211
                * [ TXQS ]: FQ-CoDel-enabled intermediate TXQs

I need your help so bad since in my country I can't find good routers to buy . I was not even able to find the TP-Link Archer C7 or the A7 . I don't want to go back to the stock firmware as I am intending to use OpenWRT for VPN, policy based routing and QoS

Appreciate your help in advance. Please let me know if you need any other information

Andy2244 · September 1, 2020, 4:43pm

Is "WMM Mode" enabled?
This was my main issue on my wrt-1200AC and speeds jumped from 30 Mbit to 270 Mbit.

Morpheus0 · September 1, 2020, 8:34pm

Hi @Andy2244,

If you could please let me know how to enable it for the 5GHz i would really appreciate it

Thanks

Andy2244 · September 1, 2020, 8:55pm

Just under the luci Network/Wireless option, edit your 5ghz adapter, than on the first page down. I think it should be on by default, so just check if its actually is.

Morpheus0 · September 2, 2020, 2:14pm

Hello @Andy2244,

Really appreciate your help here

I have already tried to enable it on 5Ghz but it did not fix anything at all:

I want to mention that I am also not getting the full speed on the 2.4Ghz, max is 50Mbps while it should be be at least 150 - 200 Mbps.

Btw, I am getting full speed using the cable connected to my laptop. There is def an issue with the OpenWRT Wireless drivers or configuration.

gaspare · September 2, 2020, 2:34pm

C6 uses the atheros ath10k open source driver.... The performace of open source driver is not equal to the closed source driver that came with the original firmware. But is improving every day

You can try the last master of openwrt. I could get a substantial increase in C6 wifi with the last ath10k driver.

Try using flow_offloading too.

Morpheus0 · September 2, 2020, 6:52pm

Hello @gaspare

Thanks for looking into this.

Since i am a beginner in OpenWRT I used the firmware in this page: https://openwrt.org/toh/tp-link/tp-link_archer_c6_v2

I am not expert in this so can you please let me know which firmware should I use here? Or do I only need to upgrade the drivers? Can you please walk me through this?

yes I have already used software flow_offloading. Before I used it it was even worse than this, I was getting 100Mbps but now it is the double after enabling it. Via cable I get 450 Mbps

Regards,

gaspare · September 2, 2020, 7:26pm

Try the devepment snapshots... See if its better for your needs...
Just know that those are development ones... Just for tests, not for production... Its just to analyze if you have an improvement....
One of the main differences is that the master build do not have the Luci gui... so, you have to do with ssh in the router....
Read this first: https://openwrt.org/releases/snapshot
You cant download the last snapshot for C6 in here:
https://downloads.openwrt.org/snapshots/targets/ath79/generic/

Morpheus0 · September 11, 2020, 2:17pm

Hello Gaspare,

I have tried to flash one of the Snapshots successfully and upgraded the firmware accordingly but the WIFI is still the same, no change at all

Is there going to be any improvement in the future? I think that I will go back to the stock firmware for now since I am not getting the full speed using OpenWRT which is sad to me

Thanks alot for your help everyone

Regards,

Morpheus0 · September 12, 2020, 9:02pm

Anyone? Can someone help here? Should I try different builds?

humanOS · December 8, 2020, 3:08pm

Try build from here, Recommended build 30 variant2

Gruntruck · December 9, 2020, 3:13pm

Hi.

How is this measurment done? You need to run iperf3 on computer wired on LAN side and iperf3 client on mobile device to truly measure throughput.

Running iperf3 server in router itself will lead to low results as SoC is not powerful enought and running both client and server on WiFi will cut speed to one third at best (as there will be lot's of collisions).

My C7 tops out around 500Mbit on 80Mhz VHT (albeit with SoC overclocked to 1GHz).

guysoft · December 9, 2020, 6:15pm

Hey,
TP-Link AC1200 Archer C6 on latest build. Also topping at about ~220Mbit .
It improved after it was on ~120Mbit when I enabled flow_offloading. But its not reaching the speed I get wired for the internet which is 300Mbit.
The fact that a setting made such an improvement makes me suspect there might be another setting that would improve it.

Also tried the developer snapshot, that broke luci and after fixing it saw no improvement.

prescott66 · January 31, 2021, 8:08am

Hi. Is this speed issue still persistent in 19.07.6 build?

prescott66 · January 31, 2021, 7:05pm

Can somebody test snapshot build, if is something changed after this commit:

Thx!

NilsRo · February 3, 2021, 7:09pm

Yes, it still persists. I have a max. rate of 150Mbit on 5Ghz instead of 600Mbit using stock firmware. By the way it is also commented in the description page and C6 uses ath79 driver. So OpenWrt is not really good usable with that difference. Does somebody know if a fixed is planned?

Stefan1 · February 4, 2021, 8:21pm

I do get around 210 mbit/s with nat and around 270 mbit/s without nat on 5ghz on an archer c6 v2 eu with 19.07.6 openwrt. I was told, that this is the price for using open source drivers. And for me that performance is sufficient. If I need it faster, I use a cable...

NilsRo · February 17, 2021, 5:51pm

With newest snapshot the performance issue is solved. Perhaps interesting for everybody.

Stefan1 · February 17, 2021, 6:23pm

What throughput do you get now ? Does the snapshot use ath10k or ath10k-ct ?

NilsRo · February 17, 2021, 7:15pm

45 Mbyte/s Up- and Download. Did not know the driver. Router is packed away. I can check next week, will mount it on monday.