@Shinobi 

You should be getting same speed on downloads you have on uploads. It appears something may be throttling your download speed. Tests you can do to narrow down where the problem might be:

You said you wired PC to Main Deco. Wire it to Satellite Deco and run speed test from PC again. You should expect to see gigabit speed, but it is worth checking.

Do you have 2.4GHz enabled on Deco Main Network? Turn 2.4GHz off.

Same idea as previous, but see if PC WiFi network driver allows you configure what bands to use and turn off everything that is not WiFi6. Leave WiFi 6 only.

Do you run Deco mesh in Router mode? Switch it to Access Point mode.

Ookla speed test app you are using allows to choose server it'll connect to. Try different servers, from those that appear to be in close proximity to you.

Do you have any other WiFi6 capable mobile device, such as tablet or smartphone? If Ookla app speed test on that device gives 800-900Mbps download and upload, that would mean the issue is with PC network adapter, and you may wish to check support forums for it. 

In fact, you may wish to check Asus PCE AX58BT support forums for anyway, because you may find good recommendations on improving adapter WiFi performance there.

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When you manage to get same 850-890Mbps on download you have on upload, you can stop on that. This is quite good speed, and while it may not be the best WiFi 6 standard promises, it is really good for home network with gigabit Internet connection.

TP-Link wrote

@Shinobi 

Thanks for the feedback.

Could you please help me check the link speed on the PC with Asus Wi-Fi 6 adapter:

How to check the associated/link speed on a wireless client

And if possible, how about the Ethernet speed from the secondary Deco X90?

@TP-Link 

Could you please help me check the link speed on the PC with Asus Wi-Fi 6 adapter

-Link speed is mostly 2.4gbps,sometimes fluctuating.

And if possible, how about the Ethernet speed from the secondary Deco X90?

-Ethernet speed connected via CAT 7 cable shows gigabit speeds at around Down900+/Up800+,which i assume is normal.

Thank you very much.

@Alexandre. 

You said you wired PC to Main Deco. Wire it to Satellite Deco and run speed test from PC again. You should expect to see gigabit speed, but it is worth checking.

- using a spare laptop with direct cable connection to the satelite Deco,I was able to achieve 900+download/800+upload, together with yesterday's results, we can safely assume ONT modem, both router Deco, satellite Deco LAN ports & my ISP is not throttling the speeds.

Do you have 2.4GHz enabled on Deco Main Network? Turn 2.4GHz off.

- turning off 2.4Ghz results in no changes to the speeds. Forcing the AX58BT wifi card to prefer 5Ghz band has no effect as well.

Do you run Deco mesh in Router mode? Switch it to Access Point mode.

- I am unable to run in AP mode as I no longer have spare router to test with.

Ookla speed test app you are using allows to choose server it'll connect to. Try different servers, from those that appear to be in close proximity to you.

- as for the ookla speedtest via browser, the upload speeds have gotten worse,dropping from 800+mbps to 600+mbps on average, tested using different servers in close proximity.

Though i suppose it looks "better" now as the download & upload speeds (500+Download/600+Upload) are now more or less equal....

Do you have any other WiFi6 capable mobile device, such as tablet or smartphone? If Ookla app speed test on that device gives 800-900Mbps download and upload, that would mean the issue is with PC network adapter, and you may wish to check support forums for it. 

- using an iphone12 mini, I am able to get 700+download/700+upload while standing next to both Decos, including standing exactly at the same spot as the PC.

So in summary;

Main Deco = OK

Satellite Deco = OK

Fiber ONT modem = OK

PCE-AX58BT wifi 6 card = SUS??

BTW, I have reinstalled the latest intel drivers for the AX58BT since its using the generic AX200 intel card drivers, no changes in the results for all the wireless tests.

In any case, thank you very much in assisting the troubleshoot, since the PC speed is quite close to the iphone12 mini speeds, I suppose I will have to live with it & hope the issues get resolved with future firmware/driver updates. Crossing my fingers,cheers.

@TP-Link 

Thanks for the initiative.

The latest test today was done with only the wifi 6 iphone12 mini & PC connected wirelessly.

For the past few days, similar tests was also done with more devices connected concurrently & at night when most people are asleep.

All results were very close with the exception of today's upload speed decreasing slightly.

Thanks.

@Shinobi 

Usually "I have forwarded your case to the senior engineers, and please check the email for further updates" kills the conversation on that forum and people rarely come back to tell how the issue was fixed. If yours will be, and you'll have time to share what was done, please do. May help someone else.

I would not settle on 500Mbps speed for device connected by WiFi6 to wired X90. Deco X90 is TP-Link top of the line hardware, it should be able to deliver more. I am getting 500Mbps on Deco M9, it only supports WiFi5. It is too bad you can't try your mesh in Access Point mode, this would have eliminated anything Deco does in router mode, including QoS and content filtering.

@Shinobi 

One more thing.

"as for the ookla speedtest via browser, the upload speeds have gotten worse,dropping from 800+mbps to 600+mbps on average"

Ookla does not recommend using browser link www.speedtest.net for speed tests on high speed connections. You should always use Ookla native app on PC and on smartphone to run speed tests on gigabit Internet.

@Alexandre. 

Oh I will definitely update if I have any progress regarding this issue,for better or worse.Many thanks for your help in this matter,Alexandre.

@Alexandre. 

Well,the screen capture showing the 3 speedtest results are from the native app, browser test was just one of the many i thrown into the mix to obtain more diverse results for comparison.

Regardless, will keep that in mind & thanks again for the great tech support & advice.