Slow downlink on 4G/5G

[vigour1]

Please tell us some basic information before asking for help:
Model Name: Zenfone 9
Firmware Version: Android 12 WW_32.2050.2050.34
Rooted or not: nope
Frequency of Occurrence: since a day, constant
APP Name & APP Version (If your issue relates to the app): testing with speedtest
In addition to information above, please also provide as much details as you can, e.g., using scenario, what troubleshooting you've already done, screenshot, etc.
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Has anyone observed extreamly slow downlnk on 5G and 4G, while 3G works just fine.
Initially I thought it's operator's fault, but switching the sim to another device has no issues and I really doubt the operator is limiting by IMEI.

web pages, video/youtube is slow and speedtest confirms that on 4G/5G I get 1mbps on downlink, while the uplink goes up to 50mbps (assuming no issue there). Again, it sounds like typical policy control, but then why on another device the speed is ok. Just wondered if anyone else is experiencing the same? Thanks.

[vigour1]

If someone hits the same problem try the following:
Go to Settings->Network&Internet->Internet->SIM 1->Auto LTE carrier aggregation (turn it OFF)
Disable 5G
Test 4G connectivity ... got restored
Enable 5G ... speed is ok now
enable again the Auto LTE carrier aggregation .. speek continues to be OK

I'm totally puzzled. Just before playing with those settings the downlink performance was terrible. I was trying multiple times to disable 5G and still had bad speed on 4G. But I always had this auto LTE carrier aggregation on. So, either it somehow affected the settings or there was some coincidence of my carrier fixing the problem while I was playing with those settings.. what would be the chance?

[ASUS_Bot]

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