Slow Speed on D-Link Dir 2640 (MT7615N)

Here is a issue but only for 5Ghz OpenWrt on MT7621/MT7615N devices with 5GHz problems

Speedtest using


Hardware TP-Link XC220-G3v Firmware :1.2.0 0.8.0 v6062.0

Over 5Ghz 80Mhz Wifi - Download 146Mbps Upload 109Mbps

D-Link Dir 2640

OpenWrt 22.03.5

Over 5Ghz 80Mhz Wifi - Download 61.2Mbps Upload 25.2Mbps

with Qosify disabled - Download 96.6Mbps Upload 107Mbps

Packages build using firmware selector

luci luci-app-wireguard luci-app-pbr stubby qosify kmod-ipt-geoip netdata usbutils kmod-usb-storage-uas block-mount kmod-fs-ext4 kmod-usb-storage kmod-usb3 kmod-usb2 kmod-usb-core

Iperf over 5Ghz

Iperf3 over 2.4Ghz

iPerf3 over 2.4Ghz 'Hardware flow offloading' Off


Iperf3 over 2.4Ghz 'Software flow offloading' Off


To see what your wifi is capable of, do not run iperf3 on the router but run it on a local wired lan client.
Running iperf3 on the router really bogs the router down.

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Using windows as server connected via Wifi and using same client phone as in previous test is giving worse results

I am far from a wifi expert and testing wireless throughput is difficult, what kind of client how many streams, bandwidth, modulation, polluted spectrum, distance etc. etc.

See: Best practices and tools for measuring wifi performance

Usually I see testing done with 4 parallel streams -P4

But a good place to start is looking at the connection of your client in Status > Overview
make sure your client is active otherwise it will fall back.

Attached picture of my Samsung S20 connected to my router, 5 GHz AX, 80 MHz clean spectrum close to router.
The PHY rate is indeed 1200 Mb/s which is the max for AX routers (Dynalink DL-WRX36) with these settings (for AC it is 866 Mb/s).

Actual iperf throughput is of course way less usually about 2/3 of the PHY rate.
In my case I measured about 700 Mb/s with iperf3 -P4

If the client and server are on the same AP, your results are approximately 50% of what you should expect.

So It is how ? 2640 gives less than 100mbps over wifi ?
onemarcfifty got 600mbps on wifi on 2660

@lleachii @egc

After that "idot" made note - I asked was it the same issue, you told me no.

Now I'm confused - I noted that posting in multiple threads would cause that.

In order to end confusion - is it possible you can just post about your WiFi issue in the thread you created for it?


You also failed to note that the OP says another user gets normal speed - so everyone is not having the same issue everywhere.


:spiral_notepad: BTW - you failed to mention that someone did indeed offer you a solution, you should visit your thread and discuss it with them. You should be patient and allow time for others to get relevant information on a 12+ year old WiFi device.

Please try:

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