RT-AC88U with Merlin Version:384.17 too slow LAN speeds

[Musafir]

First some housekeeping data

-Asus RT-AC88U (purchased 9/2019)
-Operation Mode:Wireless router Firmware Version:384.17
-Router WAN connected to Xfinity modem
-Router LAN - port 1 output connected to Netgear Gigabit switch to various LAN stations in house for TV, Receivers etc. Port 3,4 connected to nearby Playstation and Xbox
-Router Wi-Fi - Both 2.4GHz and 5GHz bands are on, laptops and smartphones connect using that
-Router USB3.0 connected to 1TB SSD serves as networked storage (NAS)
-Router USB2.0 connected to 2GB stick with 1GB swap file
- Entware, SpdMerlin, iperfv3 is installed
- HW acceleration is enabled
- NAT acceleration is Auto

The data transfer between laptop and NAS was not great. However I get rated Xfinity speeds from laptop and S10 phone so did not suspect any issue. After installing iperf on router and on laptop, I tested for LAN speed and got pathetic result. In the test below router is 192.168.2.1 and the laptop was directly connected to LAN port using Ethernet. I had disconnected all other LAN ports.

Result from laptop 192.168.2.207 directly connected at router 192.168.2.1 LAN port 1 -
----------------------------------------------------------------------------------------------------
iperf3.exe -c 192.168.2.1
Connecting to host 192.168.2.1, port 5201
[ 4] local 192.168.2.207 port 60361 connected to 192.168.2.1 port 5201
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-1.00 sec 5.25 MBytes 44.0 Mbits/sec
[ 4] 1.00-2.00 sec 7.12 MBytes 59.8 Mbits/sec
[ 4] 2.00-3.00 sec 8.00 MBytes 67.1 Mbits/sec
[ 4] 3.00-4.00 sec 8.00 MBytes 67.1 Mbits/sec
[ 4] 4.00-5.00 sec 7.88 MBytes 66.1 Mbits/sec
[ 4] 5.00-6.00 sec 7.00 MBytes 58.7 Mbits/sec
[ 4] 6.00-7.00 sec 7.38 MBytes 61.9 Mbits/sec
[ 4] 7.00-8.00 sec 7.00 MBytes 58.7 Mbits/sec
[ 4] 8.00-9.00 sec 7.25 MBytes 60.8 Mbits/sec
[ 4] 9.00-10.00 sec 7.75 MBytes 65.0 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-10.00 sec 72.6 MBytes 60.9 Mbits/sec sender
[ 4] 0.00-10.00 sec 72.4 MBytes 60.7 Mbits/sec receiver
iperf Done.

Connecting laptop by 5GHz radio gets similar result. I have seen other posts with speeds closer to 800+ Mbits/sec. What could be wrong with my router?

Then I connected two laptops to router LAN ports and tested iperf again. I got better result 312Mbits/second but nowhere close to 800 Mbits/sec

Iperf3 Result between laptop 192.168.2.189 and 192.168.2.72 both directly connected at router ports 1, 2-
---------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------
Accepted connection from 192.168.2.72, port 57773
[ 5] local 192.168.2.189 port 5201 connected to 192.168.2.72 port 57774
[ ID] Interval Transfer Bandwidth
[ 5] 0.00-1.00 sec 50.8 MBytes 425 Mbits/sec
[ 5] 1.00-2.00 sec 19.0 MBytes 160 Mbits/sec
[ 5] 2.00-3.00 sec 36.6 MBytes 307 Mbits/sec
[ 5] 3.00-4.00 sec 43.7 MBytes 366 Mbits/sec
[ 5] 4.00-5.00 sec 43.3 MBytes 363 Mbits/sec
[ 5] 5.00-6.00 sec 37.2 MBytes 313 Mbits/sec
[ 5] 6.00-7.00 sec 36.2 MBytes 304 Mbits/sec
[ 5] 7.00-8.00 sec 33.1 MBytes 277 Mbits/sec
[ 5] 8.00-9.00 sec 36.5 MBytes 306 Mbits/sec
[ 5] 9.00-10.00 sec 35.6 MBytes 299 Mbits/sec
[ 5] 10.00-10.01 sec 350 KBytes 256 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth
[ 5] 0.00-10.01 sec 0.00 Bytes 0.00 bits/sec sender
[ 5] 0.00-10.01 sec 372 MBytes 312 Mbits/sec receiver


-----------------------------------------------------------

Appreciate your help.

Additional Notes -

I have tried switching on/off STP and Jumoframes - they had no effect.
The Xfinity speeds that I get is 200Mbps DL and 6Mbps using 5GHz radio. It does not make sense that I get on 50Mbits/sec over iperf when directly connected to router LAN port. I must be missing something.

--------------------------------------------------------------------------------------------------------
CPU and Memory Data - Router does not seem to be overloaded

Temperatures 2.4 GHz: 45°C - 5 GHz: 49°C - CPU: 77°C
CPU
CPU Model ARMv7 Processor rev 0 (v7l) (Cores: 2)
CPU Frequency 1400 MHz
CPU Load Average (1, 5, 15 mins) 0.19, 0.18, 0.21
Memory
Total 503.11 MB
Free 242.57 MB
Buffers 1.86 MB
Cache 16.16 MB
Swap 0.00 / 1024.00 MB
Internal Storage
NVRAM usage 68108 / 131072 bytes
JFFS 63.24 / 64.00 MB
Network
HW acceleration Enabled

 

[Yooshaw]

I have an AX88U, and have noticed slower than expected LAN speeds as well (not as drastic as you). I was getting around 600-650Mbps on stock ASUS firmware testing through Iperf3. I hooked up an old Netgear Router I had lying around to test, and was getting around 900-950Mbps using that, so I think that ruled out any client issues.

I then switched to Merlin 384.17 to see if that would help, but the speeds were still about the same. I then tried moving my LAN drops from 1-4 to 5-8. This increased speeds to about 800Mbps - better, but still think it should be closer to 900Mbps. I'm starting to think it's a hardware issue, but need some more time for testing.

 

[Musafir]

Got some improvement after factory reset. Flashed with stock FW- Lan to Lan improved and got it in 800+ range. However, I have seen others post 900+ Lan to Lan. Reset again and this time put Merlin. Improvement persisted with Merlin. What can be done to get Lan2Lan in 900+ range.

Wi-Fi was another story. Was able to get 600+ range with S10 while standing next to router. Both laptop and router have .ac and I am using 5GHz band still was not able to get past 100-150 range on latptop. Intel AC 8265 on laptop has configuration for "Throughput Booster" which needs to disabled. After that both S10 adn Laptop have similar performance over Wi-Fi in 600 range while being next to router.

What is expected iperf3 result over Wi-Fi when Router is iperf server and laptop or smartphone is iperfr3 client?

 

[themiron]

running iperf3 on router itself involves router cpu to send/receive traffic by userpsace application.
therefore it can be slower than just forwarding/routing the traffic from one host to another (with and without hw nat acceleration).
1G lan -> ac router -> intel 8265 will give ~670Mbps with 80Mhz channel at max, if less - then air conditions are not good as can be next to router.
1G lan -> ax router -> intel ax200 will give ~900Mbps with 80Mhz channel ax max, if less - see above.
1G lan -> router -> 1G lan will give ~940Mbps, if less - check lan client cpu/eth, maybe top loaded
1G wan-> router -> 1G lan will give ~940Mbps in most cases, unless acceleration turned off, qos enabled, vpn is in use, etc

 

[Yooshaw]

I'd be interested to figure out the LAN to LAN throughput issue too - I can't get above 850 at all. Using an old Netgear router (which got around 940), I've ruled out any client or wiring issues. Seems to be a router software or hardware issue.