One of my most recent 'weird internet issues' was when I upgraded our 50mbit internet connection to 100Mbit and my laptop never really reached 100Mbit whereas my homelab easily got 100Mbit on speed tests.
It took me a while to realise the difference was that the homelab was physically connected and the laptop was using Wifi.
The laptop wifi was connected to the AP at ~1.2 Gbit and a different machine had the same issue. I decided to see what the internal network speed was and found that sending/receiving files to the homelab from a wifi device was also maxing out at ~90mbit.
This then steered me towards looking at the connection between the AP and the router, and I realised that the Wifi AP was connected at 100Mbit to the router instead of 1Gbit.
Turned out the cheap CAT7 cable that I randomly used to connect Wifi to the router because it looked nicer than the existing cable was not actually a real CAT7 cable and only provided 100Mbit. Changing the cable fixed the issue! Out of paranoia I decided to replace all of my ethernet cables with decent quality ones.
I don't even remember where that 'fake' cable came from; probably from some random Aliexpress appliance that I bought at some point. I've had similar issues with USB cables that I've amassed, where I forget where they came from and only realise later that they barely fulfil their purpose.
Dtto for video cables - once you get into 1440p/4k and high frequency rates or VBR, that HDMI 2.1 or DP 1.4 certifications start to actually matter.
What is worse is that the hardware tries hard to make it work even with noncompliant cable resulting in things like random flashes of black, or multiple random reconnections after plugging in the laptop.
I don't think so (but I am a bit tired today, so maybe something I wrote makes no sense :)).
Homelab is physically connected to the router whereas the laptop is connected via Wifi. It was the cable from the Wifi AP to the router that was dodgy which caused the issue.
I noticed because the laptop would never reach 'true' 100Mbit download speeds whereas the homelab did.
It took me a while to realise the difference was that the homelab was physically connected and the laptop was using Wifi.
The laptop wifi was connected to the AP at ~1.2 Gbit and a different machine had the same issue. I decided to see what the internal network speed was and found that sending/receiving files to the homelab from a wifi device was also maxing out at ~90mbit.
This then steered me towards looking at the connection between the AP and the router, and I realised that the Wifi AP was connected at 100Mbit to the router instead of 1Gbit. Turned out the cheap CAT7 cable that I randomly used to connect Wifi to the router because it looked nicer than the existing cable was not actually a real CAT7 cable and only provided 100Mbit. Changing the cable fixed the issue! Out of paranoia I decided to replace all of my ethernet cables with decent quality ones.
I don't even remember where that 'fake' cable came from; probably from some random Aliexpress appliance that I bought at some point. I've had similar issues with USB cables that I've amassed, where I forget where they came from and only realise later that they barely fulfil their purpose.