TP-Link Archer C60 - Slow ethernet WAN speed

Hardware Questions and Recommendations
1

Hi,

I am using OpenWrt on my TP-Link Archer C60 v2 router and I noticed that the speed I am getting is significantly slower than the speed quoted by ISP. So I did a test and was surprised to see that I was getting ~35 Mpbs from my router:

 OpenWrt 19.07.6, r11278-8055e38794
 -----------------------------------------------------
root@OpenWrt:~# speedtest-netperf.sh
2021-03-03 19:32:30 Starting speedtest for 60 seconds per transfer session.
Measure speed to netperf.bufferbloat.net (IPv4) while pinging gstatic.com.
Download and upload sessions are sequential, each with 5 simultaneous streams.
.............................................................
 Download:  34.38 Mbps
  Latency: [in msec, 62 pings, 0.00% packet loss]
      Min:  31.398
    10pct:  31.535
   Median:  31.901
      Avg:  32.004
    90pct:  32.433
      Max:  35.147
 CPU Load: [in % busy (avg +/- std dev), 59 samples]
     cpu0:  36.3 +/-  6.4
 Overhead: [in % used of total CPU available]
  netperf:  16.2
.............................................................
   Upload:  37.39 Mbps
  Latency: [in msec, 62 pings, 0.00% packet loss]
      Min:  31.235
    10pct:  31.459
   Median:  31.925
      Avg:  32.097
    90pct:  32.501
      Max:  37.712
 CPU Load: [in % busy (avg +/- std dev), 59 samples]
     cpu0:  27.2 +/-  4.0
 Overhead: [in % used of total CPU available]
  netperf:  12.5

but ~90 Mpbs when directly using the ethernet with my PC:

TheDcoder@arch /tmp> ./speedtest-netperf.sh
2021-03-03 19:20:49 Starting speedtest for 60 seconds per transfer session.
Measure speed to netperf.bufferbloat.net (IPv4) while pinging gstatic.com.
Download and upload sessions are sequential, each with 5 simultaneous streams.
..............................................................
 Download:  88.71 Mbps
  Latency: [in msec, 62 pings, 0.00% packet loss]
      Min:  31.500
    10pct:  32.200
   Median:  50.600
      Avg:  66.600
    90pct: 119.000
      Max: 131.000
 CPU Load: [in % busy (avg +/- std dev) @ avg frequency, 53 samples]
     cpu0:  15.5 +/-  7.3  @ 2160 MHz
     cpu1:   6.1 +/-  4.5  @ 2224 MHz
     cpu2:   5.2 +/-  4.5  @ 2137 MHz
     cpu3:   5.8 +/-  4.4  @ 2402 MHz
     cpu4:   5.5 +/-  4.3  @ 2123 MHz
     cpu5:   5.5 +/-  4.9  @ 2678 MHz
     cpu6:   4.9 +/-  4.4  @ 2151 MHz
     cpu7:   5.8 +/-  5.8  @ 2874 MHz
 Overhead: [in % used of total CPU available]
  netperf:   1.8
..................................................................
   Upload:  90.94 Mbps
  Latency: [in msec, 66 pings, 0.00% packet loss]
      Min:  27.900
    10pct:  29.000
   Median:  32.200
      Avg:  32.608
    90pct:  36.800
      Max:  37.800
 CPU Load: [in % busy (avg +/- std dev) @ avg frequency, 58 samples]
     cpu0:   7.7 +/-  3.4  @ 3025 MHz
     cpu1:   1.8 +/-  2.0  @ 2725 MHz
     cpu2:   1.7 +/-  1.9  @ 2690 MHz
     cpu3:   2.0 +/-  2.4  @ 2841 MHz
     cpu4:   2.0 +/-  2.7  @ 2816 MHz
     cpu5:   1.8 +/-  2.0  @ 3039 MHz
     cpu6:   1.5 +/-  1.6  @ 2724 MHz
     cpu7:   1.7 +/-  2.7  @ 3280 MHz
 Overhead: [in % used of total CPU available]
  netperf:   0.4

I believe this has been the case since quite a long time but I have never noticed it until now because I was testing out a new internet plan.

Any suggestions to what might be happening here? My router is rated for 100 Mbps so 30 is way below the limit. Thank you for the help in advance! :slight_smile:

2

The speed took a slight nose dive after I updated to 19.07, I am now getting ~30 down but a horrible ~15 up:

 OpenWrt 19.07.7, r11306-c4a6851c72
 -----------------------------------------------------
root@OpenWrt:~# speedtest-netperf.sh
2021-03-03 20:02:37 Starting speedtest for 60 seconds per transfer session.
Measure speed to netperf.bufferbloat.net (IPv4) while pinging gstatic.com.
Download and upload sessions are sequential, each with 5 simultaneous streams.
.............................................................
 Download:  29.37 Mbps
  Latency: [in msec, 62 pings, 0.00% packet loss]
      Min:  29.726
    10pct:  29.891
   Median:  30.229
      Avg:  30.308
    90pct:  30.605
      Max:  33.273
 CPU Load: [in % busy (avg +/- std dev), 59 samples]
     cpu0:  32.8 +/-  6.9
 Overhead: [in % used of total CPU available]
  netperf:  12.2
................................................................
   Upload:  13.49 Mbps
  Latency: [in msec, 64 pings, 0.00% packet loss]
      Min:  29.636
    10pct:  29.833
   Median:  30.194
      Avg:  30.262
    90pct:  30.834
      Max:  32.349
 CPU Load: [in % busy (avg +/- std dev), 61 samples]
     cpu0:  41.5 +/- 28.7
 Overhead: [in % used of total CPU available]
  netperf:   4.2
3

Running speedtest script on the router takes a lot of the router CPU so it is not a good test. Proper way to test is PC to Ethernet LAN port, with the router routing to the WAN port.

100 Mb Ethernet has a useful maximum (considering overhead) of 94 Mb. If your ISP is faster than 90 Mb you definitely need a different router with GbE ports and more CPU. The single core MIPS is more realistically used at 50 Mb ISP.

3 Likes
4

@mk24 Thanks for the answer, I didn't realize the CPU would be under such great stress when doing a speed test.

You are right, even with WiFi I am getting an impressive 93 Mbps via the router, so it is clearly no longer the beast I thought it was when I bought it 2 years ago :frowning_face:

Oh well, time to buy a better router I guess. Thanks again!

5

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