Realtek rtl8188fu Wifi adapters are too slow

Sarvesh M.D

11/19/22, 8:10 AM

I have an rtl8188fu wifi adapter and I have installed driver for it from https://github.com/kelebek333/rtl8188fu . My problem is that the network speed is too slow. I have tried the wifi adapter on another Windows computer and it was fast. But when I use it on my Ubuntu 20.04 LTS Desktop, it is very slow. It hardly reaches 3 Kilobits per second. With this I came to know that the problem was not with the adapter itself, but with the driver or the Operating System.

I have tested it with Google, https://speedtest.net, speedtest cli, fast.com, etc. It's really weird that it reaches more than 50 Kilobits per second on windows while it cannot get more than 3 Kilobits per second on Ubuntu. Help me on this problem.

203

1 + 2

wireless

drivers

guiverc

11/19/22, 8:18 AM

You didn't clarify if you were talking about Ubuntu 20.04 LTS Desktop or Server (they have different default as to default hardware stack), but have you tried using the other hardware stack? (*mentioned as it's something easy; drivers being kernel modules are thus related to the kernel or kernel stack being used - given LTS releases come with two stack choices...*).

Sarvesh M.D

11/19/22, 8:44 AM

I've edited the question to mention that it is a 20.04 LTS Desktop

Score:1

Ubuntu

waltinator

11/19/22, 1:01 PM

Check your WiFi MTU, using

ip link

also notice your WiFi interface's name.

The MTU (Maximum Transmission Unit) is the size of the largest packet that can be sent in a single network transmission. If a packet exceeds the MTU of a link, the data must be split into multiple packets (fragmented). These multiple packets must be sent over the link, received, acknowledged, and reassembled at the far end. If your link is misconfigured, and you have to fragment every packet you send, your actual data transfer rate drops.

Ethernet (wired) networks use an MTU of 1500 bytes.

Due to additional per packet overhead for WiFi (8 bytes PPPoE header), WiFi uses an MTU of 1492.

Your MTU should be set by your DHCP server, check your router's config.

You can set your own MTU (setting does not persist over restarts) with

sudo ip link set dev name mtu 1492

where "name" is the interface name from above.

Here's an example:

walt@squid:~(0)$ ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp63s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT group default qlen 1000
    link/ether 00:24:21:7f:e5:1c brd ff:ff:ff:ff:ff:ff
3: wlxf46d04b1790f: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DORMANT group default qlen 1000
    link/ether f4:6d:04:b1:79:0f brd ff:ff:ff:ff:ff:ff
walt@squid:~(0)$   sudo ip link set dev wlxf46d04b1790f mtu 1492
[sudo] password for walt: 
walt@squid:~(0)$ ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp63s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT group default qlen 1000
    link/ether 00:24:21:7f:e5:1c brd ff:ff:ff:ff:ff:ff
3: wlxf46d04b1790f: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1492 qdisc mq state UP mode DORMANT group default qlen 1000
    link/ether f4:6d:04:b1:79:0f brd ff:ff:ff:ff:ff:ff

My WiFi "interface name" is "wlxf46d04b1790f".

0 + 1

Sarvesh M.D

11/19/22, 4:02 PM

Thanks for your answer. I did what you suggested with my WiFi inteface name, but it didn't show any improvement :(

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Realtek rtl8188fu Wifi adapters are too slow

TH: อแด็ปเตอร์ Realtek rtl8188fu Wifi ช้าเกินไป

RO: Adaptoarele Wifi Realtek rtl8188fu sunt prea lente

RU: Wi-Fi адаптеры Realtek rtl8188fu работают слишком медленно

VI: Bộ điều hợp Wifi Realtek rtl8188fu quá chậm

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