s21 Wifi slow speed

[Members_gRHQSV5]

Hi,

After latest may update speeds on wifi are very slow. On WiFI5 there is 100 Mb/s download, sometimes even lower, more like 40-60Mb/s. Compared with other devices and there are normal operational speeds - 350-400Mb/s.
Speeds were weasured with speddtest android app, but same results are collected with other speed test tools or fast.com

Actions I've performed so far:
- restart phone
- restart network settings
- restart home AP, router and other network devices

phone -> Samsung s21 5G
Access point -> unifi AP nanoHD
router -> edgerouter x

BR,
Damian

[Members_Ved7fB8]

I have the same problem since Sunday (8th May). Mine is a S21 5G also. I've tried the same actions too with no improvement.

[JAMES4578]

Hi @Members_gRHQSV5 @Members_Ved7fB8 , did you perform the recommended practice  after the update such as wiping the cache partition and running the Galaxy App Booster from Galaxy Labs or the Repair apps option in the Recovery Menu.

To wipe partition:

1. Turn off the device.
2. Connect To Computer or plug in USB-C Headphones , Press and hold the Volume Up key and then press and hold the Power key 
3. When the Android logo displays, release all  keys.
4. An 'Installing system update' message will show for 30 - 60 seconds before the Android system recovery menu options appear.
5. Press the Volume down key several times to highlight wipe cache partition.
6. Press Power key to select.
7. Press the Volume down key to highlight yes, them and press the Power key to select.
8. When the wipe cache partition is complete, Reboot system now is highlighted.
9. Press the Power key to restart the device.

Same procedure for Repair apps except obviously select Repair apps at stage 5.

[leicesterMan]

Shouldn't need to do all this, the phones are over 1000 pounds, it's like buying a car, every time up fill it up , you got to get in touch with the manufacturer to go through a process of starting the damm thing , pathetic

[AWheal]

I too am experiencing this issue.

I have a Samsung S21 Ultra and a Ubiquiti wireless AP.

My laptop on the same network connects at over 300mbps and sometimes my phone too but recently it keeps dropping to below 100mbps, in fact as low as 30-40mbps when we have a Virgin gigabit internet feed and a Ubiquiti Gigabit network.

All ethernet cabled devices work fine as well as other Wi-Fi connected devices, just my Samsung S21 Ultra which confirms it is device specific problem to solely my device.

I have tried deleting the partition as per the above suggestion by JAMES4578 as well the other tests that Members_gRHQSV5 has performed above.

The problem seems intermittent as sometimes I can achieve the expected connection speed but since the last software update it seems to be an issue for me.

Am running a SM-G998B/DS on Android version 12 and One UI version 4.1

Any suggestions greatly appreciated. 🙏

[fallenwout]

I have the same. But it is not internet speeds, I got it to the point where my security cameras on the same network (intranet) switch to lower resolution saying "poor network quality".

[thw2]

I own S21 5G. Updated to Android 13, One UI 5.0.

Have a 1 GBps plan at home.

Turned off cellular data. Connected to wifi to test speed.

On ASUS RT-AC1200G+:

On TP-Link RE450:

Pretty decent results. Guess results depend on router wifi speed, network speed and proximity to wifi source.