Traffic Analyzer reduce WAN/Download speed by half

[BOFH]

Hi Guys,

It took me a long time until I realized that if the traffic analyzer is enabled, your internet speed is somehow cut by half. I was looking in different directions and never thought that the speed fault is related to my router RT-AX88U (FW: 384.18). I was pointing my ISP for this issue.

Today I wanna share with you the evidence (>900Mbps when TA is disabled AND <=700Mbps when TA is enabled):

It's really a mess with the traffic analyzer and there's no notification/notice that let you officially know that if enabled you cut your download speed by half.

 

[ColinTaylor]

The spdMerlin results are not a valid test because it is testing the speed between the router and the internet, not the LAN and the internet. So unlike LAN clients spdMerlin cannot fully exploit hardware acceleration which may lead to unrepresentative results. Retest your speeds using a LAN client.

 

[BOFH]

Hi ColinTaylor,

It has nothing to do with the LAN speed. I'm talking about the WAN speed.
LAN speed is ok when doing LAN activities. But testing internet speed by a LAN client connected to the router via cable is same as testing the speed from the router.
Also the HW acceleration, should affect LAN and not your WAN speed

I can confirm that the issue is on the "Traffic Analyzer.", I have done different tests now like connecting a laptop directly to the cable modem the internet speed is "pure" 1G. I can reach the same speed on my Asus by disabling the "Traffic Analyzer" otherwise it's like cut by half (500-700M)

It's also visible on the screenshot, the spdmerlin can almost reach 1G when "Traffic Analyzer" is disabled.

 

[Adamm]

But testing internet speed by a LAN client connected to the router via cable is same as testing the speed from the router.

Incorrect, the point Colin is trying to make is that your router has significantly less CPU power then your LAN devices. So by running the speedtest binary on your router you will get inaccurate/inconsistent results at high speeds due to CPU usage, whereas any modern LAN devices won't have this limitation and produce more consistent results.

 

[BOFH]

Incorrect, the point Colin is trying to make is that your router has significantly less CPU power then your LAN devices. So by running the speedtest binary on your router you will get inaccurate/inconsistent results at high speeds due to CPU usage, whereas any modern LAN devices won't have this limitation and produce more consistent results.

I understand the point that other devices my have more power and get better result. But here again it's enough evidence that the router is able to reach my 1G as soon as I disable the TA. No matter CPU or not result are here and you can see it clearly, After disabling TA, the speed is back to >900Mb. it's obvious no ?


.

 

[pattiri]

So the answer is clear I guess, when TA is enabled (with the other services that you're using) the CPU of your router can handle max about ~560 Mbps.

 

[ColinTaylor]

I understand the point that other devices my have more power and get better result. But here again it's enough evidence that the router is able to reach my 1G as soon as I disable the TA. No matter CPU or not result are here and you can see it clearly, After disabling TA, the speed is back to >900Mb. it's obvious no ?

No, you're still missing the point because you don't understand how hardware acceleration works. Test again using a LAN client (even one with a weak CPU). You may or may not end up with the same results, but at the moment all you're testing is how TA interacts with a process running on the router. The traffic flow is completely different for WAN to LAN transfers.