Broadband very odd speed issue

Hi
I am hoping that someone can assist with a perplexing issue that is really frustrating me.
Set up
Fibre modem providing gigabit ethernet
Laptop directly connected via cat 6 ethernet cable to modem - speeds at laptop 900Mb/s plus download and much the same upload - very happy with that.
LG Oled C2 4K TV in the opposite corner of the room together with Sky Q box. This is the problem area. I am told by Sky and many others on the sky forums that the lan port on the sky q box is capped at 100Mb/s however when I connect a cat 6 cable directly between the modem and the Sky Q box I get 350 to 450Mb/s as measured on the netflix speed tester. If I remove the cable from the Sky q box the connection defaults back to wi-fi and |I get 90Mb/s. If I plug the cable back in and retest it goes back to 350 to 450Mb/s. The wifi speed in my room as measured on my IPhone is 350 to 450Mb/s which tallies with the speed on my TV with the ethernet cable connected. I am well ware that I dont need gigabit speed at my TV for it to work properly. That for me is not the issue I dont understand how I get 350 to 450Mb/s with the ethernet cable connected and 90Mb/s when I remove it. Also, I dont really want a cable running across my room (or to be more accurate my wife does not) if I can avoid it. I would be most grateful if anyone has any thoughts on this issue.

Sounds as though the port is probably Gbit, but internal processing caps that. Look at the port on the modem - there will often be two small LEDs telling you teh connection speed - what is it?

WiFi at 90Mbps - possibly capped by the SkyQ.

I just googled what speed a 4K TV needs and it seems 25Mbps is probably sufficient. So 90Mbps should have no problem at all.

Am I missing something?

Sounds to me that the issue is with the WiFi adapter (or whatever it’s called) in the Sky kit.

Are you with Sky Broadband or a different ISP ?

NOTE that Sky Q is a strange beast, it doesn't want to just connect to an existing WiFi, it wants to RUN the WiFi as a mesh system for the whole home. Assuming you are using Sky Broadband with a Sky router, using WiFi with the Q box means it is in charge, so that any Mini boxes around the house are connected correctly.
https://www.trustedreviews.com/how-to/fix-sky-q-conn...

If I had a single Sky Q for TV and was not using Sky Broadband, then I would probalby try and run an Ethernet cable discreetly around the room.

A decent router will show you the connection speed and mode that the client device is using. My ASUS RT-AX88U shows me that my Yamaha Amp is only able to use WiFi 4 (N) on 2.4 GHz, so in an attempt to stop slowing down my other devices I use an Ethernet connection to stream radio to the amp. (This is 100 Mbps) as the amp and router are quite close. More modern iPhone 15 can connect to the router at WiFi 6 (AX) with theoretical (PHY) speeds of upto 1.2 Gbps.

But the OP isn't saying he has a problem with watching the TV. Just that he doesn't understand how the Netflix speed tester is reporting very high speeds via Ethernet. He says "I am well aware that I dont need gigabit speed at my TV for it to work properly. That for me is not the issue".

See my previous post. 90Mbps is apparently more than three times the minimum necessary speed for his system. He doesn't mention connected Mini boxes having problems.

It seems to me simply a desire to understand what is going on. Which you and others are providing. A solution doesn't seem to be needed, as an ethernet cable is unnecessary.

My guess would be that what device the Netflix speed test is running on (unclear whether it's the TV or the Sky Q box) just doesn't have the CPU power to handle a gigabit speed test.

In reply to a post by pluralist:

See my previous post. 90Mbps is apparently more than three times the minimum necessary speed for his system.

If its a 4K television watching 4K (UHD) content on Netflix then the average is 25 Mbps, but it can peak higher. On non-Netflix sources (e.g. iPlayer 4K) the data rate is much higher... for example live content can't be pre-processed for best bit-rate.

That said 90 Mbps sounds fine, and we don't have much detail. Either the TV (usually they are underpowered) or the Sky Q box is running the "Fast.com" website. I don't think they've ever created an app, its meant for use on phones, laptops, tablets. Some TV's have poor web browsers.

Thank you all for your thoughts. Pluralist you have it I am trying to understand it. My router is a you fibre gigabit router which via my laptop gives me gigabit download and upload but at my TV gives me 350-400Mb/s. The suggestion that the Sky Q box is the cause seems the most likely but how is the burning question. I dont get it and Sky cant explain it. Thank you all again for trying to help if I ever find a reason that makes sense I will post back.

In reply to a post by wobblymike:

Thank you all for your thoughts. Pluralist you have it I am trying to understand it. My router is a you fibre gigabit router which via my laptop gives me gigabit download and upload but at my TV gives me 350-400Mb/s. The suggestion that the Sky Q box is the cause seems the most likely but how is the burning question.

Are you running the speed test on the TV using a web browser, or on the Sky Q box?

If the TV then the suggestion is that this as fast as the TV can go when you give it a faster connection.